Journal archives for August 2021

August 09, 2021

Timothy, more of a mystery than you might think

I've been checking identifications of Timothy Grass (Phleum pratense) since mid-2019. The level of misidentification on iNaturalist is . . . interesting. My list is below. If the plant is not a grass, its family name is added in parentheses. Sorry about providing only scientific names.

Although I'm sure humans often misidentified Meadow Foxtail (Alopecurus pratensis) without computer assistance, I think many of these names originated as suggestions by the CV (computer vision program), which seemed to consider anything with a more or less cylindrical inflorescence made up of many little bits to be Timothy. Given the state of identifications for Timothy, this was understandable; the computer is trained on iNaturalist photos and if many of them are misidentified, errors result. I hope that recent corrections help the latest CV version to recognize Timothy more precisely. Of course, even if CV improves, we humans have to choose from among the CV suggestions and are also entirely capable of misidentifying Timothy independently.

Plants identified as Phleum pratense. The first four species listed are very commonly misidentified as Phleum pratense on iNaturalist, and I've seen the others at least once.

Alopecurus pratensis
Alopecurus arundinaceus
Plantago lanceolata (Plantaginaceae)
Phalaris aquatica
Agastache sp. (Lamiaceae)
Agropyron cristatum
Alopecurus aequalis
Ambrosia sp., probaby A. artemsiifolia (Asteraceae)
Anemone cylindrica (Ranunculaceae)
Anthoxanthum odoratum
Apera interrupta
Holcus lanatus, immature
Baptisia sp., immature (Fabaceae)
Betula sp., catkin (Betulaceae)
Carex acutiformis (Cyperaceae)
Carex barbarae (Cyperaceae)
Carex kelloggii (Cyperaceae)
Carex obnupta (Cyperaceae)
Carex pendula (Cyperaceae)
Carex sect. Racemosae (Cyperaceae)
Carex sp. (Cyperaceae)
Celosia spicata (Amaranthaceae)
Chamaelirium luteum (Melanthiaceae)
Cynosurus cristatus
Dalea candida (Fabaceae)
Dactylis glomerata, immature
Eleusine indica
Elymus sp.
Gastridium phleoides
Hordeum brachyantherum
Hordeum sp.
Hypochaeris radicata, in bud (Asteraceae)
Itea virginiana (Iteaceae, formerly Saxifragaceae)
Lepidoptera (a moth caterpillar on a grass stem)
Liatris spp. (Asteraceae)
Muhlenbergia sp.
Pennisetum glaucum
Pennisetum setacea
Phalaris arundinacea
Phalaris caroliniana
Phleum alpinum
Phleum arenarium
Phleum sp.
Plantago coronopus (Plantaginaceae)
Plantago patagonica (Plantaginaceae)
Poa arachnoidea
Polypogon monspeliensis
Populus tremula, catkin (Salicaceae)
Salix sp., catkin (Salicaceae)
Secale cereale
Setaria faberi
Setaria pumila
Setaria viridis
Triticum aestivum (club wheat, T. a. compactum)
Verbascum thapsus (Scrophulariaceae)
a blond middle school boy with freckles (likely correct, in one sense)

These have been misidentied as Phleum alpinum (in the broad sense):
Carex breweri (Cyperaceae)
Carex scopulorum scopulorum (Cyperaceae)
Carex spectabilis (Cyperaceae)
Carex section Ovales (Cyperaceae)
Cynosurus echinatus
Phyteuma nigrum (Campanulaceae)
Trifolium pratense in fruit (Fabaceae)

On the other hand, these names have been applied to what was actually Phleum pratense:
Acorus calamus (Acoraceae)
Agastache sp. (Lamiaceae)
Alopecurus pratensis
Ammophila breviligulata
Carex sp.
Koeleria macrantha
Phalaris canariensis
Phalaris aquatica
Toxicoscordion venenosa, in fruit (Melaniaceae, formerly Liliaceae)

Posted on August 09, 2021 18:15 by sedgequeen sedgequeen | 6 comments | Leave a comment

August 06, 2021

What to photo -- Carex sedges

Identifying Carex on iNaturalist is really hard. Why? First, Carex are diverse (about 2000 species worldwide, close to 500 in North America north of Mexico), and these simple plants have fewer traits than most. Second (partly a result of the first), differences between species are often subtle and often involve a combination of multiple traits. Third, the photos on iNaturalist often don't show the needed traits. You can do something about that third one.

The list below explains the most important traits to photo for Carex identification. Of course, even perfect photo sets may languish unidentified for a while, because Carex identification knowledge is mostly local (another result of that diversity) so even Carex "experts" don't know many of them.

What if you don't photo all these things? Sometimes you don't need to. Sometimes one or two photos are enough. Trouble is, if you don't know what species you're dealing with, you probably don't know which traits you need.

  1. Habitat. Most Carex are microhabitat specialists, so this can be an important clue. You can just make notes, rather than photo, but was it growing in water? In a bog? Lake margin? In upland forest? Prairie? Roadside salted in winter? On serpentine or pumice or other unusual soils?
  2. General appearance. Is the plant cespitose (growing in one clump) or rhizomatous (spreading by rhizomes)? Is the inflorescence nodding or erect? Is it obviously green or blue-green? If the photos don't show these traits well, try to get enough information to remind you, and write about it.
  3. Inflorescence. Are the spikes crowded or separate? Is the lowest inflorescence bract longer or shorter than the whole inflorescence? In some cases (especially if the individual spikes are short) it's important to know if the staminate flowers were at the base or top of the spike, so include a close photo.
  4. Perigynia. Unless the spikes reveal most of the length of the perigynia ( +/- = utricles, fruits), break up a spike and spread the perigynia on your hand (or any other convenient surface) and photo them. Try to show both sides. Get close enough to see the hairs, if the surface is hairy. While you're doing it, include some of the scales (bracts) that grow between the perigynia.
  5. Leaf sheath front. As in grasses, the sedge leaf consists of a blade (usually flat, the part we think of as a leaf) and a sheath (which wraps around the stem). Where's the front? The blade attaches to the back of the sheath -- think of Superman's cape attaching to his shirt. The front of the sheath is the other side, where the big S is on Superman's shirt. The front is usually hyaline (transparent when fresh, whitish when dry). In a few species, it may be green and veined like the back. The front may be brownish or coppery. It may have tiny red dots. The top of the sheath (at the level where the blade attaches) may be flat across or concave, but in a few species it extends upwards like a sheath. In a few species the top is thickened. The sheath may be "cross rugulose," with horizontal waves or corrugations. In many species, the leaf sheath decays leaving a network of fibers.
  6. Plant bases. Some Carex are green all the way down, but in some the lower parts of the leaf sheaths are conspicuously reddish, brown, or black.

(6.5) In certain Carex of eastern North America, the leaf sheath back is also important. Not so much in the Pacific Northwest.

(6.6) The ligule is important in some species, though I don't use it in the ones I know. To photo, pull the leaf blade a little away from the culm (stem) and photo the triangular area where the blade is held tight to the culm by a little membrane.

Posted on August 06, 2021 22:11 by sedgequeen sedgequeen | 5 comments | Leave a comment

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