Nassella (Stipa) pulchra vs cernua
Can Nassella (Stipa) pulchra and cernua be distinguished macroscopically? - a working post that I'm updating as I learn more and as folks comment on the post. Thanks @aparrot1 , @hkibak, @yerbasanta, and @keirmorse for comments / contributions that have improved the post substantially.
(Note: @keirmorse provided a new key in a comment on this post (see below) on 11/15/23. I haven't had a chance yet to update the body of the post with information from the new key.)
The context here is centered on Fort Ord where pulchra and cernua range widely in a largely overlapping way (Styer 2019), and where one might want to learn more about the how the two species differ in range and habitat without having to pull out the macro lens for every single plant. To do this, one must first know how to identify them (e.g. with a macro lens, hand lens, or dissecting scope) and then extrapolate from that to a recognition of naked-eye characters that might correlate.
There is also some important nomenclatural context. The taxa have changed names several times. The story is quite complicated (Barkworth 1990, Columbus & Smith 2010), but the main thing to know is that Nassella pulchra and Stipa pulchra are synonymous, and Nasella cernua and Stipa cernua are synonymous. The synonymy arises from the history where Nassella was originally a subgenus of Stipa in 1830, then it's own genus in 1853, then a subgenus again in 1901, then a genus again in 1942 and 1947, then deleted (?) in the peer-reviewed thread in 2010. And regardless of the level of Nasella, species pulchra, while having been first described as Stipa pulchra in 1915 was not placed under any version of Nasella until Barkworth put it there in 1990. Species cernua was was first described as Stipa cernua in 1941 (Stebbins & Love), and then also moved by Barkworth in 1990 to become Nassella cernua. The genus Stipa was for a time abandoned in 1993 by Buckworth, all of it's contents having been transferred to other genera in Tribe Stipeae, and then resurrected in 2010 by Columbus & Smith based on genetic work e.g. by Jacobs et al. (2007). Genus Stipa stands today (including pulchra and cernua) in the Jepson Manual (2nd ed., 2012). iNaturalist goes with Nassella pulchra & cernua, not Stipa, being based on Plants of the World Online, which doesn't yet (2022) correspond to Jepson 2nd ed in several areas. If you think I've gotten any of this wrong, let me know.
It's all about the lemmas. The characteristic that pulled all the species into Nassella is the way the lemma wraps completely around, overlapping itself and completely concealing the palea etc. And, it is a lemma characteristic - hairiness - that also separates pulchra and cernua in the latest Jepson Manual treatment.
The story of how cernua differs from pulchra appears to begin in 1941 with a paper by Stebbins & Love. They note:
"Several people, including the present writers, have noticed that this species as recognized in the current manuals actually consists of two distinct types. One, with deep green foliage, relatively broad leaves, stiffer panicle branches, large glumes, thick, fusiform lemmas, and stout, stiff awns, is predominant in the outer Coast Ranges and the wooded parts of the Sierra Nevada foothills. This is typical S . pulchra, of which the type came from Healdsburg, Sonoma County. The other form, with somewhat glaucous foliage, narrower leaves, flexuous, often nodding panicle branches, smaller, narrower glumes, slender lemmas, and slender, often flexuous awns, occurs chiefly in the treeless parts of the inner Coast Ranges, the San Joaquin Valley (in scattered areas undisturbed by cultivation), the valleys of southern California, and the edges of the deserts. The two types have been given different common names, typical S . pulchra being known as purple needle grass, and the slender, interior type as nodding needle grass."
This is wonderful to come across, because it distinguishes the two taxa entirely on naked-eye characters. Obviously, we need the hand-lens characters to be sure, but we can get a pretty good clue from the above before deciding whether to pull out the hand lens.
Stebbins & Love also provide a map of the relative abundance of the two taxa at about 60 locations throughout California. The Monterey area has both, and it's clear from the map that there's potential that within the Monterey area, one would find pulchra in more coastal, mesic, and higher-elevation situations and cernua in more inland, xeric, and lower elevation situations. Interestingly it's hard to discern this from Styer's (2019) detailed maps of the distributions within Fort Ord, perhaps because Fort Ord does not exhibit much variation in the above characters.
The new taxon Stipa cernua started showing up in floras and other broader treatments in a paper on Stipa by Dedecca (1954), then Munz & Keck's state-wide flora (1959), followed in county-wide works, for example, by Thomas (1961) in Santa Cruz county and Hoover (1970) in San Luis Obispo county. It shows up as Nassella cernua in Barkworth's treatment in the Jepson Manual (1993) and in Matthews (1997) for Monterey County. But then it flips back to Stipa cernua in Columbus et al.'s treatment in the 2nd edition of the Jepson Manual (2012, print version, and online version as at May 2022) following a paper by Columbus & Smith (2010) based on genetic work by Jacobs et al. (2007). Note that species cernua didn't appear in the 1951 state-wide Jepson publication, despite this being after Stebbins & Love (1941), presumably because the 1951 Jepson Manual was actually a posthumous re-publication of Jepson's 1923 and 1925 works.
Regardless of the name changes at the genus level, pulchra and cernua have stood since 1941 as two distinct species. But, the characters used to discriminate them in keys have varied widely. For example:
- Stebbins & Love (1941) uses leaf width, lemma shape, caryopsis length, awn shape, awn:lemma ratio.
- Munz & Keck (1959) uses lemma shape, leaf width, leaf color, awn shape, awn:lemma ratio
- Thomson (1961) uses awn:lemma ratio, leaf color
- Hoover (1970) uses awn length
- Barkworth (1993) in Jepson Manual uses awn shape
- Matthews (1997) uses awn length, culm length, glume length, lemma length
- Columbus et al. (2012) in Jepson 2nd ed. uses lemma hairiness
- Matthews & Mitchell (2015) uses lemma hairiness, awn length, culm length, glume relative lengths
One might seek out a definitive differentiation in the current Jepson Manual treatment by Columbus et al. (2012). Here the key (for genus Stipa) separates pulchra and cernua solely on lemma hairs - pulchra being hairier.
Couplet 8:
- 8. Lemma body in age glabrous in distal 3/4 except on veins ..... S. cernua
- 8' Lemma body in age hairy throughout ..... S. pulchra
https://ucjeps.berkeley.edu/eflora/eflora_keys.php?key=11182
The species descriptions by Columbus et al. reveal more distinctions. About 20 characters are listed in the descriptions for both taxa. Some are useful to the question of separating pulchra and cernua. Pulchra has wider flatter leaf blades, and pulchra has hairier leaves and lemmas. Other characters are a bit of a wash, such as stem height, blade length, and inflorescence length.
Notably, several distinguishing characters used in previous floras are absent from Columbus et al.'s treatment. And yet, I suspect that several of them remain helpful.
So, in the quest for clues as to how one might instantly distinguish the two taxa in the field, perhaps it is helpful to step back and look in turn at all the characters that have ever been used to differentiate them. I'll attempt this here, starting with "macroscopic" characters that you might recognize without even breaking step on a hike, and then working down through "mesoscopic" characters that you might recognize with a floret in hand, ultimately to "microscopic" characters for which a at least a hand lens might be needed.
Macroscopic characters
Leaf color
Pulchra foliage usually deep green. Cernua usually glaucous. Stebbins & Love (1941), Munz & Keck (1959), Thomson (1961).
Leaf width
Unrolled pulchra leaves are wider, with little to no overlap with cernua. Pulchra culm leaves 2.4-6 mm. Cernua 1.2-2.4 mm. Stebbins & Love (1941), Munz & Keck (1959), Thomson (1961).
Culm length
Culm length overlaps substantially between the two species. Pulchra 6-10 dm. Cernua 6-9 mm. Munz & Keck (1959). Differing among authors e.g. Matthews (1997), Matthews & Mitchell (2015).
Panicle shape and flexion
Pulchra "spreading, or slightly cernuous". Cernua "slender, flexuous or cernuous". Stebbins & Love (1941).
Glume color (purple or not)
Purpleness of glumes does not seem to be clearly an indicative character. The word "purple" appears in the common name of pulchra, and in casual reports mentioned by Stebbins & Love. But I haven't yet found it mentioned as a clearly differentiating character in any keys or floras (yet), nor have I yet observed it as such in the field. Stebbins & Love's description of cernua refers to the glumes as "pale reddish or purple". Matthews (1st and 2nd ed.) list purple color as a character for pulchra but not an absent character for cernua. Columbus et al. (2012) online key does not mention color in relation to these two taxa. The species descriptions also do not mention purple color, other than in the common name for pulchra. One can find purple glumes in the non-"purple" taxon. For example, here's a Fort Ord cernua with purple glumes: https://www.inaturalist.org/observations/117652776
When it has been mentioned, purpleness only seems to have ever been mentioned in relation to glumes (see references above), which are what you see when you look at an inflorescence as a whole. In contrast, color differences have never been mentioned to my knowledge in relation to lemmas, for example; lemmas being what you see when you pull a floret out of a spikelet, leaving the glumes still attached to the rest of the plant.
Also, presumably, any colors of glumes, lemmas, etc. vary with season - generally becoming more pale with age.
Inflorescence nodding
"Cernua" means "nodding", hence the common name for cernua "Nodding needlegrass". But interestingly, Munz & Keck attribute the "nodding" character to pulchra and not cernua, and Stebbins & Love (1941) attribute some degree of cernuosity to both species.
Location, geomorphic setting, soil type, and associated plant species
In some parts of the state, location should give a strong clue as to which Nassella/Stipa species you're seeing. But in the Monterey area, location within this area seems to be a weak indicator, as evidenced by the somewhat overlapping ranges mapped by Styer (2019), whose 70 mapping units within the former Fort Ord average 400 acres in size. In areas smaller than this where both species occur in a broadly overlapping way, one ought to be able to learn the ways in which geomorphic setting and soil type act to determine which of the Nassella/Stipa species would flourish. And perhaps a similarly determined correlation with other plant species might be learned as a clue to which Nasella/Stipa species to expect. In the Monterey Area, this might align generally with the differentiation between Northern Coastal Grassland and Valley Grassland (sensu Holland & Keil 1995), for example. While broad gradients obviously extend across the Monterey area, much of the pertinent differentiation could be described as a "complex" or "mosaic" rather than a broad contiguous dichotomous boundary.
Mesoscopic characters
Lemma width or shape
When you pluck and examine a Nasella floret and ignore the awn, the lemma is most of what you are seeing. In this genus, the lemma is rolled around on itself completely with opposite margins overlapping. The lemma is like a tube with a bulge. At it's proximal end, there's a "callus", and at its distal end, there's a "crown", followed by the awn. Inside, the palea is concealed, along with the ovary or caryopsis, depending on maturity.
Variation in lemma thickness is one of the first things I noticed when I looked at my first 20 or so macro images of Nassella florets (https://www.inaturalist.org/observations?place_id=any&taxon_id=52806&user_id=fredwatson&verifiable=any) and this variation is also one of the obvious differences evident in this wonderful photo by Keir Morse: https://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0520+0704.
Pulchra lemmas are "thick" and "fusiform". Cernua's are "slender" and "cylindrical". Stebbins & Love (1941), Munz & Keck (1959)
Interestingly, lemma width or shape is not mentioned in the latest Jepson treatment (Columbus et al. 2012).
Awn shape and flexion
Pulchra awn "stout, stiff". Cernua "slender, flexuous beyond the second bend". Stebbins & Love (1941), Munz & Keck (1959), Barkworth (1993).
Awn:lemma ratio
Cernua has longer awns relative to the lemma. Slightly different ratios are reported by different authors:
- Pulchra awn or 5.9-9.8 x lemma. Cernua 8.7-14.5 x. Stebbins & Love (1941).
- Pulchra awn or 7-9 x lemma. Cernua 9-12 x. Munz & Keck (1959), Thomson (1961).
Awn length
Cernua has longer awns in absolute measurement, although there is substantial overlap between the two species. Pulchra 60-90 mm. Cernua 60-100 mm (Stebbins & Love, 1941). See also: Hoover (1970), Matthews (1997), Matthews & Mitchell (2015).
Glume length
Cernua has longer glumes, although there is substantial overlap between the two species. Pulchra lower glume 15-26 mm. Cernua 12-19 mm (Stebbins & Love, 1941). See also: Munz & Keck (1959), Matthews (1997)
Glume relative lengths
Cernua glumes differ more between lower and upper glumes (first and second glumes). I think Stebbins & Love (1941) might have missed this character, but it was picked up by later authors. Pulchra second glume "slightly shorter" than first. Cernua "shorter". Munz & Keck (1959), Matthews & Mitchell (2015).
Microscopic characters
Upper glume venation
Pulchra 3-5. Cernua 3. Stebbins & Love (1941).
Lemma venation
Pulchra 5-9. Cernua 5-7. Stebbins & Love (1941).
Lemma length
Pulchra lemmas are generally longer, but there's substantial overlap between the species. Munz & Keck (1959) state pulchra lemma length 7.5-13 mm, and cernua 5-10 mm. Other authors use slightly different values with the same general theme (Matthews 1997, Columbus et al. 2012).
Columbus et al. (2012) also measure the callus and crown lengths in fractions of a millimeter - with pulchra having a generally longer callus (proximal end of the floret), and longer (but less distinct) crown (distal end of the floret, before the awns).
Lemma hairiness
Pulchra lemma more hairy, described in various ways by different authors. Munz & Keck (1959), Columbus et al. (2012), Matthews & Mitchell (2015).
Lemma papillosity
Cernua lemma papillose. Pulchra not indicated, other than by implication through hairiness. Hairiness and papillosity are somewhat contrasting characters, as far as I can discern from plants in general. Munz & Keck (1959)
Caryopsis thickness at maturity
Pulchra 1-1.4 mm. Cernua 0.6-1 mm. Stebbins & Love (1941).
Epilogue
One thing's for sure, both taxa are deserving of the epithet "pulchra". They are both pulchritudinous - i.e. "beautiful" - especially in May.
It would be great to continue hearing folks' thoughts on all this. My intent would be to try to incorporate information from comments into the main text of the post.
Comments
Hi Fred, Thanks for sharing this--lots of good info here!
Thanks Irene. I think what I'll probably do is expand the original post text to a broader summary of these taxa. I'd like to try stay rooted in documentation (i.e. publications) and photographic evidence (i.e. iNaturalist, CalFlora). I'm new to journal posts on iNat, so hopefully this turns out to be a useful mode for exploring a taxon related topic with discussion. I'm hoping I can keep editing the original post over time as more is learned. Not sure.
Thoughts that popped into my head as I read... Because much of Fort Ord soil belongs to the Arnold/Santa Ynez xeropsamment type, I think we can have "xeric/interior" plants found here such as cernua alongside the expected pulchra. And that is what Styer reports in his distribution maps. In fact, when using the Keybase filter for eJepson on plants from Fort Ord I have discovered that I have to use CW (Central Western California) instead of CCo (Central Coast of California), despite Fort Ord falling within the bioregion map of the CCo provided by the Jepson Herbarium... otherwise I miss out on many plants found on Fort Ord. https://ucjeps.berkeley.edu/eflora/filter_keys.html In a recent update, the Jepson Herbarium has essentially recognized the same (See Note).
Many plants are easy to distinguish and key out when one has all taxa in the key right at hand :-) "Characters" such as "hairier" can be meaningless if you only have one plant at hand and have never seen the others.
I've looked at some of the references you provided, and in this case, simple leaf width seems diagnostic and in my future observations I will include my millimeter ruler:
2.5-6mm across = pulchra
1.4-2.4mm across = cernua
I agree with you re: purple as a character after looking at Keir Morse's photo, and will perhaps agree more or less strongly when I myself have seen 20 examples of each species in the field at the same time of year.
Wonderful post Fred! I had my doubts on what to call the 'purple needlegrasses' in the area, and I think this all gets to the heart of the matter.
I am a big fan of going from micro to macro-level observations to distinguish species, for a few reasons, and funnilyy enough, I still see purple as a (somewhat) distinguishing characteristic, with S. cernua ironically appearing more purple in your Keir Morse's photos than S. pulchra.
Thanks for the notes @hkibak and @yerbasanta. Regarding purpleness, one thing to keep in mind is that the purple characater referenced by Matthews (& Mitchell) relates to the glumes not the lemmas. When we see purple in the plant from a distance, we're seeing the glumes, whereas the color difference evident in Keir's photos relates to the lemmas. I updated the post to emphasize this a bit more.
Regarding soil type etc., yes, your comment @hkibak stimulated me to develop a section in the post that addresses this a bit: "Location, geomorphic setting, soil type, and associated plant species".
Good summary. I've been working on this recently as it has been on my mind for awhile. The photo of mine you linked to is from when I finally saw S. cernua after keying S. pulchra out to S. cernua for years using the 2012 Jepson key. I can confirm that both that key and the Flora of North America key are very wrong and will lead to lots of misidentifications. I've done some work recently focusing on herbarium specimens and measuring up florets including the awns. I think someone should look at the leaves and such with fresh material as they were used in past keys but the material on herbarium specimens is mostly not great for assessing those. Below I include my current draft of a potential revision for the Jepson key. I would focus on these characters and see how well they align with vegetative characters. I currently don't have the awn thickness in the key but that is something to consider. S. pulchra has generally thicker/stouter awns than S. pulchra. I'm not sure how to draw a solid line with those though. How straight or wavy the terminal segment of the awns are seems to vary even on a single specimen. S. cernua is finer and more likely to be wavy or curved. S. pulchra can be straight but is often at least somewhat curved and sometimes wavy. Anyway, here's the draft key, which would just replace part of the 2012 Jepson key. Note that this gets complicated by S. manicata, which there isn't much information on and which, in turn, makes it difficult to provide a solid couplet regarding S. manicata.
6a Lemma crown generally distinct from rest of lemma, crown 0.5-1.2 mm .....7
6b Lemma crown transition to rest of lemma somewhat to very obscure, crown 0.1-0.6 mm .....8
7a Lemma crown ± 1/5 lemma, lemma body in age distally ± glabrous; awns 30-50 mm ..... S. manicata
7b Lemma crown <= 1/6 lemma, lemma body in age distally ± glabrous or pubescent; awns 38-100 mm .....S. pulchra
8a Awns 12-55 mm long, 0.1-0.2 mm thick at the base; lemma body in age hairy between veins in distal half ..... S. lepida
8b Awns 50-110 mm long, 0.2-0.3 mm thick at the base; lemma body in age generally glabrous between veins in distal half (rarely hairy) ..... S. cernua
Many thanks @keirmorse. I look forward to trying out this new key.
I just made a post with some photos here:
https://www.inaturalist.org/journal/keirmorse/93201-how-to-distinguish-nassella-pulchra-stipa-pulchra-from-nassella-cernua-stipa-cernua
@keirmorse Oh no.... I had already made a key based on what you posted above!
Using the Keir Morse Key (2023) to modify Jepson
See https://www.inaturalist.org/journal/fredwatson/66303-nassella-stipa-pulchra-vs-cernua
1a Florets 2–6 per spikelet ..... S. mauritanica
1b Florets 1 per spikelet
2a Palea grooved lengthwise
3a Blade 0.8–1.5 mm wide; awns 10–16 mm ..... S. purpurata
3b Blade 0.2–0.4 mm wide; awns 15–25 mm ..... S. chaetophora
2b Palea flat
4a Leaf tips sharp, stiff; lemma awn glabrous to scabrous; fruit ribbed
..... S. brachychaeta
4b Leaf tips acute to acuminate, not both sharp and stiff; lemma awn glabrous to
scabrous or hairy; fruit not ribbed
5a Lemma margins in age strongly overlapping entire length, lemma body generally
bumpy throughout, tip with crown; palea 1/4–1/2 lemma, glabrous, veins 0
6a Lemma crown generally distinct from rest of lemma, crown 0.5-1.2 mm .....7
6b Lemma crown transition to rest of lemma somewhat to very obscure, crown 0.1-0.6 mm .....8
7a Lemma crown ± 1/5 lemma, lemma body in age distally ± glabrous; awns 30-50 mm
..... S. manicata
7b Lemma crown <= 1/6 lemma, lemma body in age distally ± glabrous or pubescent;
awns 38-100 mm .....S. pulchra
8a Awns 12-55 mm long, 0.1-0.2 mm thick at the base; lemma body in age hairy between
veins in distal half ..... S. lepida
8b Awns 50-110 mm long, 0.2-0.3 mm thick at the base; lemma body in age generally
glabrous between veins in distal half (rarely hairy) ..... S. cernua
5b Lemma margins in age generally not or only ± overlapping at least part of length, or strongly
overlapping in some species with smooth lemmas; lemma bodies generally smooth proximally, tip
generally 1–2-lobed; palea 1/3 to ± > lemma, 2-veined at least proximally, generally hairy,
or both lemma and palea glabrous
good thing it was just for personal use :-)
Can't wait to try the lemma crown approach in a few weeks!
@hkibak I think the current version of the key is only slightly different. The overlap in 6a got bigger to account for a few Channel Islands S. pulchra specimens with shorter lemma crowns.
Purple color in S. pulchra is mainly the result of domesticated exotic animal grazing, removing soil phosphorus below original pre-European levels, so when plant needs to relocate phosphorus to make seeds, they steal from other parts of the plant which turns purple. See the photos in the third edition of Howard Sprague's 1964 book "Hunger Signs in Crops" Very common in the overgrazed Great Basin sagebrush grasslands, where the weed grasses are starving from phosphorus and turn red or purple.
In California, wherever the weed grasses replaced the natives, then a grazing-overlap was able to be made, and a period of a completely barren landscape was avoided . Once the native grasses were exterminated, the wild oats and others weed grasses continued the removal of soil nutrients by the grazing animals, to the point that many of California grasslands cannot support native grass populations in 2024, the nitrogen, phosphorus, calcium and organic matter in the top two inches, have dropped belong the thresholds for native seedling survival.
Even if a magic wang was waved over the weed grasses, and they disappeared tomorrow, without replacing the missing nitrogen, phosphorus, calcium and organic matter, the natives cannot grow back.
You can easily test this, by taking 4-5 inches of soil and pout it in a container, and bake it at 200 degrees F. for an hour or two to kill any seeds. Do a soil test of that same soil. Then sow local native seeds and water every day, so that water is not part of the experiment. Then see if the seedlings sprout and grow to maturity, if if they die of starvation at only a few inches tall, as they did for one of my projects at https://www.ecoseeds.com/good.example.html
The awn stiffness is the easiest method, S. cernua is head-hair like, whereas pulchra awns are much stiffer. I hold the seed and then use my finger to bend the awn.
Have run into a problem in my project at the Kite Hill Wildflower Preserve, with a new species of Stipa which is a fertile cross between S. pulchra and S. lepida, much larger plants than the typical pulchra which still grows in the area. Probably a higher chromosome number that the other two. A much more robust plant, able to compete with the wild oats.
After doing a common garden study of the Stipa pulchra, Elymus glaucus and Bromus carinatus populations of the nine Bay Area counties of the SF Bay area in 1991, found major morphological differences, and the only consistent difference between S. cernua and S. pulchra was the stiffness of the awn.
Has anyone had success or issues with my draft key?
@dremann You saw my study? https://www.inaturalist.org/journal/keirmorse/93201-how-to-distinguish-nassella-pulchra-stipa-pulchra-from-nassella-cernua-stipa-cernua
The only consistent difference I found was the lemma crown but it wasn't easy to quantify the awn stiffness. Based on the thickness of the awn, I'd say most S. pulchra were much stiffer than S. cernua but some did seem to possibly be of intermediate stiffness/thickness. I'd be curious what the lemma crown is like on the hybrids you mention and why you don't think they could possibly be an introduced species. I've heard of infertile hybrids. My study was small and only focused on the flowers/fruit but I have wondered about other characters as I've seen some ridiculously tall S. cernua plants. I did sample S. lepida as well, which is not shown, but I found only a few specimens that could arguably have been intermediate. Those best fit S. cernua but with especially hairy lemmas.
I wanted to work on Ft Ord grasses this spring and summer, including Nassella but I've been stuck in Central Oregon. So not yet.
Check Dr. Stebbins & Love's 1941 article "AN UNDESCRIBED SPECIES OF STIPA FROM
CALIFORNIA" in Madroño Vol. 6 and on page 139 comparing the awns of S. pulchra and cernua. It is that longer and more flexible awns that gives the two species away most easily.
However, the problem in California in general with grass taxonomy, is that the species are described from a type specimen and does not have a way to include all of the hundreds of variations which the ecotypes present. Until we have a method to describe ecotypes, then sorting out individual species by trying to shoe-horn all of those variations into a single type specimen description will be very difficult.
Another very huge California native grass taxonomy issue which Dr. Stebbins and I wrote about-- Stebbins, G. Ledyard and Craig C. Dremann. 1998. "Jepson Manual chromosome numbers may indicate new "cryptic" native grass species." GRASSLANDS 8 (3): 4-5
Is that we have about 300 already described native grass species in California, and because these grasses have changed their chromosome numbers as grasses commonly do to get bigger and more robust, there are 100 more grass species to be described and named--which look very much like their ancestors but because they can no longer reproduce are now new species.
We were working one morning at Dr. Stebbins' dining table, and I asked him, what does it mean in the Jepson manual when a grass species has multiple chromosome numbers in the Jepson Manual, And he said, there are more than one species there, and we proceeded to write the paper.
Not to throw a money-wrench into your very detailed work, but I think we need to rely on genetics to sort out exactly what species are which, because the physical taxonomic methods have already missed 100 species which are lurking and are waiting to be discovered and described.
In my own case yesterday, when I was collecting the type material for my new S. pulchra x S. lepida population at the Kite Hill Wildflower Preserve in the Town of Woodside, I was very surprised to find a second new species of Stipa. The original species grows at the intersection of S. lepida in the shade, and the S. pulchra in the sun. The fertile cross is a more robust plant growing about 3X bigger than the original S. pulchra.
However, the S. lepida also changed, it borrowed genes from the S. pulchra to form seeds exactly like S. pulchra, No other physical changes other than swapping their original very small dark seeds, with the silvery large pulchra seeds.
If you go through Dr. Stebbins' literature at https://www.ecoseeds.com/stebbins.html he encountered this swap between ELymus and other related genera at--
Stebbins, G. L., Jr., J. I. Valencia and R. Marie Valencia. 1946. Artificial and natural hybrids in the Gramineae, tribe Hordeae. I. Elymus, Sitanion, and Agropyron. American Journal of Botany 33: 338-351.
Stebbins, G. L., Jr., J. I. Valencia and R. Marie Valencia. 1946. Artificial and natural hybrids in the Gramineae, tribe Hordeae. II. Agropyron, Elymus and Hordeum. American Journal of Botany 33: 579-580.
Gramineae, tribe Hordeae. III. Hybrids involving Elymus condensatus and E. triticoides. American Journal of Botany 36:291-330.
Stebbins, G. Ledyard, Jr., and Ranjit Singh. 1950. Artificial and natural hybrids in the Gramineae, tribe Hordeae. IV. Two triploid hybrids of Agrpyron and Elymus. American Journal of Botany 37: 388-393.
Stebbins, G. L., and Antero Vaarama. 1954. Artificial and natural hybrids in the Gramineae, tribe Hordeae. VII. Hybrids and allopolyploids between Elymus glaucus and Sitanion spp. Genetics 39: 378-395.
Stebbins, G. L. 1957. The hybrid origin of microspecies in the Elymus glaucus complex. Proceedings of the International Genetics Symposia, 1956: 336-340.
Stebbins, G. Ledyard, ed. Craig C. Dremann. 1998. Elymus glaucus: a collection of polyploid cryptic species. GRASSLANDS 8 (4): 3, 11.
Your "ridiculously tall"plants could be a new species which is a fertile hybrid between S. cernua and another Stipa species growing nearby, as my two new species in Woodside were produced. Maybe time to roll out the DNA testing, too bad the really cheap method of the 1990s does not exist any more. The isoenzyme gels run off the seed proteins and using esterase to produce the banding patterns only cost $5 each, and I ran over 2,000 that you can see at https://www.ecoseeds.com/gels.html
@dremann Yep, some solid DNA work needs to be done to sort them all out properly and it is getting cheaper. So, hopefully someone will take that on. I definitely found some weirdos and there certainly could be some cryptic taxa.
That said, my main goal was to make a key that worked most of the time for the currently defined taxa and I think my key works better than the rest, many of which cause a lot of misidentifications. Using the awn stiffness is great if it works for you, but it is pretty hard to quantify that stiffness at all stages of maturity/dryness and put it in a key that works for people that aren't very familiar with the taxa already. It's similar to an old Malacothamnus couplet that was stout vs slender stems. It's arguably obvious if you compare specimens side by side or are already very familiar with the species, but where is the magic line between stout and slender that a novice could use to understand what you mean by those terms, especially if they haven't seen both taxa?
@keirmorse so true about keys. They have to be written through the eyes of a complete newcomer to the genus by someone who has looked at hundreds of examples of each of the species.
When I read sentences such as "No other physical changes other than swapping their original very small dark seeds, with the silvery large pulchra seeds." @dremann , I think "Transposable Elements." For example, the Mutator system of transposable elements is common in grasses and capable of just that sort of genetic change (see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC65609/). While it is exciting to see such a change, and you are to be congratulated for noticing it, I don't think it merits being called a new species unless other criteria are also met.
As a grad student I accidentally left a tray of Hopi Blue Corn Seedlings in the back of my car under glass on a sunny spring day. When I got back the car windows were steamy and most of the seedlings looked wilted. I planted out a few of the seedlings. The following year I was going to do some work on Hopi Corn physiology so I planted out a row of just one ear from one of those surviving seedlings. I was shocked. By tassel time it seemed like I had every mutation known to maize biology in that row. Every single one of the seeds I planted had grown, over 300 of them. But I had purple plants next to green ones. Green and white striped plants. Giant plants over seven feet growing immediately next to 18" plants. Plants producing tassels out of cobs. Plants with curling leaves, narrow leaves, broad leaves, tubular leaves. Huge kernels, tiny kernels, speckled kernels, and of course pink, white, blue kernels. It was quite a surprise. Especially that all survived and that all were from the same cob, so highly genetically related. It turned out that I had activated one of the Mutator Transposable Elements by Heat Shock.
@dremann The phosphorus hypothesis is really compelling, I hadn't heard it before, but it is a worthwhile hypothesis to test. Maybe it explains why addition of composted material can be beneficial for native plant restoration, especially on degraded/invaded lands.
I have noted myself that areas where woodchips have been dumped and spread have seemed to spontaneously grow large patches of bunchgrasses which are absent or in much lower concentration than in surrounding areas, so it may in part explain these results. I'd myself chalked it up to some combination of increased organic matter, acidity, and microbial shifts, but macronutients may also be contributing here.
@hkibak fascinating description of an unintentional experiment, I hadn't heard about this sort of effect, but I had suspected there must be some sort of epigenetic or other mechanism allowing plants to rapidly adapt to their environment over a few generations.
Sorry to get off-track on the grass ID discussion, but these were two very interesting points that stuck with me reading over the recent discussion.
@yerbasanta -- At the Kite Hill Wildflower Preserve in the town of Woodside, California in San Mateo County, between San Francisco and San Jose, is half way between two other serpentine belts, the SFPUC Crystal Springs watershed/Edgewood Preserve 5-10 miles north, and Jasper Ridge 5 miles to the south.
Also, I-280 cuts this serpentine block in half, with 22 acres of the Caltrans "Wildflower Reserve" to the east, off Farm Hill Blvd. Cañada College which is a small hill off Farm Hill is surprisingly all chert.
What I am doing at Kite Hill is soil tests from the top two inches of around the desirable serpentine natives with Waypoint Lab (Anaheim) A-01 soil tests plus organic matter, costs $48 total, with a full one quart sample of soil taken from the top two inches from right next to the base of the target plant. The report is written as "data only in a bar graph format" and the sample is sifted through 1/4 inch mesh screen to remove rocks and vegetable material.
Then, do soil samples where there are weed or barren erosion issues, like you would find at an old mercury mine tailings or serpentine asbestos mine spoils, from the top two inches also. Then bring the weed area or the barren area, back to "Craig's Soil nutrient and Organic matter Thresholds" needed by your target desirable plant.
We had an area along the I-280 fence line, where the I-280 trail is closest to Jane Drive near the Castle House. Then, 15 feet from the fence and going 200 feet down the slope to the gully, was a completely barren serpentine moonscape with zero vegetation and was severely eroding after each rainfall. Picture of the "before" at https://www.ecoseeds.com/1-before-serp-fertilizers.jpg
Then, adding blood meal for nitrogen at 1,280 pounds per acre, and bone meal for phosphorus at 800 pounds per acre, produced about a one mm. layer on that barren slope--picture with the white bone meal which was put down first, then the blood meal on top at https://www.ecoseeds.com/1-repairing-serp-fertilizer.jpg
Then, a top coat of Super Soil potting mix about 3 mm thick, all done in February 2023. Was not expecting that in the barren serpentine gravel was dormant native seeds, which this spring produced a 99% weed-free meadow, picture at https://www.ecoseeds.com/1-sm-after-fertilizers.jpeg
A transect of the restored Kite Hill Preserve barren serpentine on February 24, 2024:
Goldfields - 55% cover
Vulpia microstachys - 27% cover
Tidy Tips - 12% cover
Poppies - 6% cover
Weeds - Zero
In another Kite Hill area of yellow star thistle, did the same soil tests where 3 million YST seedlings were growing at the rate of 5 seedlings per square inch on 3/4 acre. Added the organic fertilizers and mulch, and 90 days later 90% of the YST were gone, and the native tarplants sprouted up.
However, the main method I use to restore the 14 acres, is to mow monthly at 8-12 inches high, and that is producing 95-98% weed-free wildflower meadows, when the dormant native seeds in the soil get a chance to get some light and water, and get the terrible weeds off their backs.
I am teaching classes at Kite Hill in July and August about my methods at https://www.ecoseeds.com/2024-classes.pdf and you can come and see my two new-to-science Stipa species at the same time, evolution in real time. Pictures of the results of our monthly mowing shown on that PDF flier.
Otherwise the preserve is open 24/7, just park behind the Jane Drive gate and walk in through the pedestrian gate which is always open. April and May are always guaranteed Super Blooms, you can see pictures at https://www.desertusa.com/wildflo/ca-north.html from May 24 and April 1st. We had 300,000 yellow mariposas in May.
Fascinating! I have some extra compost that I might try adding to my yard, or even areas where I've been pulling YST, hemlock, and other thistles from beneath oak canopy to see if that has any impact, since some of these areas I have been weeding for years now.
I think the idea of frequent, relatively high mowing is intriguing as well, it matches my observations of moderate disturbance via foot traffic on trail edges and junctions being higher in bunchgrass and native plant density as well.
I'll have to see this Kite Hill area, it looks like iNaturalist has some before and after observations already?:
https://www.inaturalist.org/observations?nelat=37.44237889259962&nelng=-122.24698394459088&place_id=any&swlat=37.44003631737931&swlng=-122.25838333290417
@yerbasanta ...Glad to see people recorded my yellow mariposa Super bloom in May. Eight years ago and until two years ago, we only had 5,000 blooming on the top ten acres. The mariposa need absolutely weed free conditions, and a cover of the native Vulpia microstachys to be able to grow unmolested. I call those plants my "Mowing-graders" they are giving me an A-Plus wherever they sprout and bloom, showing where I am now 95-98% weed free. Then last year and this year, 300,000 showed up as you can see in the pictures submitted.
In terms of fertilizers and organic matter, you need to run some quart samples of soil from the top two inches from around the weeds you want to get rid of, and from around the natives you want to convert that area to. Run the A-01 plus organic matter with the Waypoint lab in Anaheim for $48.
One of my last weeds in spots are circular to oval patches of solid V. myuros in amongst a sea of native V. microstachys which because of its height you cannot get rid of it by mowing--I call it my "Meadow Rash"--you must fertilize just like star thistle, soft chess, medusahead, filaree, wild geranium, cheatgrass and star thistle--all of these weeds are there because soil nutrient levels are too low for the native thresholds.
So to convert the Vulpias, add blood meal for nitrogen, to bring the 7 ppm myuros levels up to the 14 ppm microstachys level. And sprinkle some bone meal to bring the phosphorus myuros level of zero (not even one ppm), back up to the 5 ppm needed for the microstachys to be able to take over in the place of the myuros.
Originally we only had a few hundred of some species of rare plants growing along trailsides, where people were stomping on the weeds, which allowed the natives some light, water, access to soil nutrients, and eliminating the allelochemical effects of the exotics on the natives. Now we have tens of thousands to tens of million of some of those plant now.
What is quite surprising, is the species where I have only old plants and no seedlings because I have not fertilized around them yet, to bring those soils up to the thresholds needed for seedling survival. Those are the Poas, Melica grass, buckwheat, milkweed, and coyote mint--less than a dozen of each on the whole preserve. That means those species at Kite Hill will age out and are "Zombis" and disappear over time.
That means for the monarchs in California, along with their milkweeds disappearing by our plowing and spraying, are those populations also disappearing because they have stopped reproducing and their baby milkweeds not surviving because of soils which are below their threshold levels?
If anyone is interested in coming to see the summer super bloom, and see my two new species of Stipa, I will be having a class about mowing and fertilizing in July and August at https://www.ecoseeds.com/2024-classes.pdf
"Before and after" pictures of the fertilizing serpentine at https://www.ecoseeds.com/serp-repairs-fert.pdf and mowing at https://www.ecoseeds.com/2-before-after-mowing-sm.jpg, and converting the yellow star thistle at
https://www.ecoseeds.com/2-YST-before-after-sn,jpg
The conversions by adding fertilizers were done in 90 days, and the mowing conversion took two years.
There is a whole treasure chest of dormant native seeds in California underneath the weeds, and if you are persistent with your monthly mowing at 8-12 inches high, and do your soil tests and add the necessary fertilizers and mulch--even to serpentine soils-- in California, like Kite Hill you can get 5-10 native seedlings to sprout up and be able to do some "Botanical Archaeology"
As a kid I always wanted to dig up some buried treasures, never expecting it would be unearthing entire intact native grassland ecosystems, from exactly where they grew last 150-200 years ago.
The star thistle link is https://www.ecoseeds.com/2-YST-before-after-sm,jpg
@fredwatson ...Seems like you and the readers of this Stipa taxonomy discussion have a wealth of details and insights, which would be very valuable to be able to describe and publish papers on the two new Stipa species which have been discovered at the Kite Hill Wildflower Preserve in San Mateo Count in the Town of Woodside?
Anyone interested in helping put those paper together to become co-authors? I think the format of Dr. Stebbins and Love's publication when they named Stipa cernua in Madroño in 1941, could be a good format to follow. email= craig@ecoseeds.com
Thanks for the tag @dremann. It would be a bit outside my bandwidth and expertise to publish on a new Stipa at this point though :)
@dremann Likewise for me. I have several research projects I want to work on but don't have the time or money for them. It's ridiculous how many CA plant genera still need a huge amount of research to sort out basic taxonomic questions. I just did my quick Stipa study when I was unemployed for a few months. Malacothamnus took over 6 years working mostly full-time on it and that still needs more research, but I'm not doing it. Hope you find some takers!
@fredwatson ... @yerbasanta ..."Craig's SURE-FIRE method to sort S. pulchra from S. cernua" -- try and set the dry seed stalks on fire with a butane lighter!
Last year I was doing burn tests of one square foot of different California natives to compare the burn time and temp. with one square foot of exotics--by placing the dried stems in a 13-quart stainless steel mixing bowl, with a K-type pyrometer you get from ebay with a 8 inch long probe, and a butane BBQ lighter.
You can see from my videos at https://www.youtube.com/channel/UCHl6YA4PvegxYo3TxSGOs9Q that the Stipa cernua burned like a torch, whereas the Stipa pulchra straw when being held upright, would not catch fire. This is a huge discovery for wildfires in California--if we can convert the flammable weed grasses, back to the original Stipa pulchra grasslands wherever they occurred in the past, we will essentially be putting back an asbestos blanket on the land--especially when we include the tarplants, which in my burn-test video would not carry fire as well.
Whereas our wild oats, after mowing looks visually very fire-safe, but still leaves tons of flammable fuel on the ground, and actually makes the fires worse than if we had never mowed at all.
The upright unmowed weed grass straw has air spaces between the stems, so the fire burns hot but very rapidly. However, the mowed straw on the ground, you have eliminated that air space, and concentrated that straw into straw-briquettes, so not only burning at over 1,000 deg. F., it now burns for 9-16 minutes--turning our California grasslands into giant pizza ovens.
The best and only permanent solution is to convert the flammable weeds back to fire-safe wildflowers and native grasses.
@dremann Would you be able to migrate this thread to a different journal post? The intent of my post (and most of my posts) is to discuss identification. It would be easier to keep track of things if you made a separate post about Stipa / Nassella ecology. Thanks!
Thanks all I wanted to contribute--if anyone tries "Craig's SURE FIRE method to sort S. pulchra from S. cernua" using a butane bbq lighter let me know. I have only tried it on the serpentine population of the S. pulchra at Kite Hill, and do not know if it would apply to any other S. pulchra populations across the state.
I'm sure the Jepson eFlora would love to have a key couplet using flammability. LOL. Very interesting though.
@fredwatson ...@yerbabuena --Ping me if anyone wants to migrate "Native grass and wildflower meadow restoration" discussions elsewhere.
Check out my YouTube videos of the exotic huge flames vs. natives, with the exception of the S. cernua which went up like gasoline,. And that particular species is a huge issue wherever is is growing underneath the solar panel farms located in Southern California, and could potentially burn billions of dollars of investment to ash.
The Stipa grass in north Africa has enough carnuba-like wax that it is harvested commercially, and that is probably what makes S. cernua so flammable. That may also make S. cernua in the future an important dual-use agricultural crop in California--this perennial would not need to be replanted each year, and the stems would be harvested for wax first, and then pulped to make paper. The Stipa pulp in North Africa is used for paper-making in the UK.
Source--"Plants for Man" by Robert Schery page 364.
@dremann Please start a different journal post. To do this, you can go to your Profile page, click Journal, and then New Post.
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