Blackberries are notoriously difficult to identify, so this page is dedicated to describing the differences between two species that are found together on Keats Island: The European/Vested Blackkberry (Rubus vestitus) and the Himalayan Blackberry (tentatively Rubus bifrons). I made this guide to organize my own learning, so I hope it might be helpful to others as well.

Note on names:
The taxonomy of blackberries is very messy and complicated, because blackberries are able to reproduce asexually. This means that there are many different lineages of clones, and it is difficult to decide what counts as a species and where the limits are between different species. They can also hybridize and produce new hybrid lineages. The abundant introduced blackberries here in the Pacific Northwest are usually called "Himalayan Blackberry", but it is not clear exactly what species they are, or how many species/lineages have actually been introduced. They are often referred to as Rubus bifrons or Rubus armeniacus. I have no opinion on this as I am not a blackberry specialist, so I will refer to them as Rubus bifrons for simplicity, with the caveat that this name may prove incorrect once genetic studies have clarified which lineages are in our region and the taxonomy becomes settled... if it ever does! At any rate, these "Himalayan Blackberries" can be recognized and distinguished from Rubus vestitus which is also introduced here in Southwestern BC, and probably many other areas in the Pacific Northwest and elsewhere.

Primocanes vs Floricanes:
Before identifying a blackberry, it is necessary to know the difference between two types of branches: primocanes and floricanes. These branches have different ID features, so looking at the wrong one can given you an incorrect ID. While blackberry bushes can live for many years, their individual branches live for only two years. In the first year, a shoot sprouts out from the ground and begins to grow as a long sprawling vine. This is the primocane, and it will not produce flowers. In its second year, that branch will switch to producing side branches that are tipped with flowers. Those are floricanes. At the end of the season, the entire branch will die, ready to be replaced by the next one. As a result, the bottom of a blackberry thicket becomes full of dead branches. In summary, if you see flowers/fruits/buds on a branch, that is a floricane. The thick branches that are attached to the ground (i.e. they are not side branches) are primocanes.

Caveat:
All of these photos are taken on Keats Island in British Columbia, Canada. They represent the range of variation that we see here, but may not reflect the range of variation across other parts of the species range.

First, here is a quick summary of two key ID features:

Key feature #1: Hairs on primocanes

The easiest feature to check is the presence or absence of dense hairs on the primocanes. Rubus vestitus is covered in a vest of hairs that give it a fuzzy look. These catch the light and can be noticed even at a moderate distance. Himalayan Blackberry have hairless primocanes, giving them a sharper look. Beware that both species including Himalayan Blackberry do have hair on the floricanes, so make sure that you are looking at the primocanes - the branches that are very thick and do not have berries/flowers/buds. Himalayan Blackberry can have some scattered hairs on the primocanes, but is not densely hairy.

This photo shows the hairy primocanes on Rubus vestitus

This photo shows the lack of hairiness on Himalayan Blackberry.

Key feature #2: Stipitate glands in inflorescence

This ID mark is harder to see, but still very useful. If you look very very closely at the inflorescence of Rubus vestitus, you will see numerous stipitate glands amongst the hairs. These are tiny sticky globs suspended upon long stalks. Himalayan Blackberry lack these stipitate glands. Both species have hairs in the inflorescence, so it is necessary to look very closely to differentiate them from stipitate glands: Hairs end in a fine point without a sticky blob at the top, and the stalks of the stipitate glands are thicker and shorter than the hairs. You might be able to make them out with an extremely keen look with bare eyes, but it is much easier to zoom in with a magnifying glass or macro lens. I turn my binoculars backwards to use it like a microscope - it may look silly but works very well: put what you want to look at right up against the eyepiece and look through the wrong end of the binoculars. You can find the stipitate glands (or lack thereof) on the pedicels or the branch within the inflorescence of Rubus vestitus.

Here is what the stipitate glands look like on Rubus vestitus:

Compare to the lack of stipitate glands on this Himalayan Blackberry:

Detailed photo accounts

These species accounts contain my observations of the species on Keats Island. I included a lot of extra detail that is not necessary for a quick ID, but might be helpful for tricky cases.

Rubus vestitus

This species has the common name "European Blackberry", which is a bit nonsensical given how many hundreds of species live in Europe. An alternative named is "Vested Blackberry", coined by Stewart Wechsler, alluding to the vest of hairs around the stems that is key to their identification.

Floricane

The floricane is the stem that produces flowers/fruit. They are usually shorter than primocanes, and end in a single inflorescence. There are often many floricanes coming from the same primocane. They have several evenly spaced leaves arranged in an alternate pattern. In the axil of each leaf is a bud, and these buds grow into the pedicels of a single flower, or a short branch with 3 flowers.

Floricane: Flowers

The flowers of Rubus vestitus are pink, and can vary from deep magenta to nearly-white with only the faintest blush of pink. On plants with nearly-white flowers, the newly opening buds may be pinker than the fully expanded petals of older flowers. The flowers generally have dark pink stamens, but paler flowers can have white stamens.

While they normally have 5 petals, flowers with extra petals are common.

The sepals end in a point, giving the buds a beaked appearance. I've noticed that the pointed tip of the sepals is longer on the Keats Island Rubus vestitus than it is on the Himalayan Blackberries, and also that the sepals have prickles that the Himalayan Blackberries lack, but I don't know how consistent these differences are in other populations.

The inflorescence is at the tips of the floricane branches (terminal) and can have 7-35 flowers/fruits. The flowers are clustered (technically, cymiform or thyrsiform).

Floricane: Stipitate glands

The presence of stipitate glands in the inflorescence is an excellent field mark, but hard to see without a magnifier. These photos are at the limit of my camera's ability. I can sometimes just barely make them out with my bare eyes, but only after seeing what to look for under the magnifier. Since the stipitate glands are shorter than the hairs, it is also very difficult to feel the glands.

Stipitate glands can be found in the pedicels or branches within the inflorescence. They can also be found on the stem below the inflorescence, but become more sparse as you go down the stem away from the inflorescence, so require a closer search.

These photos are of the branch within the inflorescence (the branch in between individual flowers).

Floricane: floricane leaves

The floricane leaves usually consist of three leaflets. Less commonly, some leaves may be divided into five leaflets. The leaflets are variable in shape, but are generally more rounded than Himalayan Blackberry, particularly the terminal leaflet. The rounded leaves end with a short triangle at the apex.

The uppermost leaf sometimes is only a single leaflet (i.e., a simple leaf).

Like Himalayan Blackberry, they are hairy above and below, giving them a soft fuzzy feel on the top (adaxial) surface. The top seems fuzzier than Himalayan Blackberry leaves, at least on Keats Island.

The leaves farther down the branch (away from the growing tip) often have the lower leaflets more deeply lobed, almost dividing the leaf into 5 leaflets. Floricane leaves that are fully divided into five leaflets seem to be much more uncommon than on Himalayan, but they do occur.

The underside of the leaves (abaxial surface) are tomentose, giving them a gleaming silvery appearance. They are hairy, especially along the veins, and the midvein is armed with strong prickles.

At the base of each leaf is a pair of small stipules.

Floricane: floricanes branches

Like the primocanes, floricanes are hairy, prickly, and often maroon. Their dense layer of hair is denser than the branches of Himalayan Blackberry. While Himalayan blackberry also can have hairy floricane branches, the hair seems to be more scraggly and sparse, laying haphazardly along the stem, while the hair of Rubus vestitus is dense and erect in a smooth layer.

Primocane

Primocane: primocane leaves

The primocane leaves usually have five leaflets. The terminal leaflet is generally more rounded than it is in Himalayan Blackberry.

Prickly undersides:

When the leaves are growing, the terminal leaflet has a long point, but as the leaflet expands, it broadens into a broad oval that is less pointy than Himalayan Blackberry. Be sure to look at the shape of the older, fully expanded leaves lower or the stem, and ignore the shape of the immature leaves near the growing tips.

Primocane: primocane branches

Primocanes are strongly armed by prickes. The size of the prickle correlates with the size of the branch, with thinner, weaker prickles on the thin branches and strong, robust prickles that can tear clothing on the thicker branches. All branches have a dusting of fine hairs, even the thickest primocanes.

The colour of the branches can be deep maroon purple, especially in the sunlight. The shaded undersides of the branches can remain green, giving the branches a bicoloured pattern. Deeper branches in the shade can remain entirely green, especially those that creep along the ground. Branches can have any intermediate amount of red, and apparently some in Europe can be all green, but every bush I have seen on Keats Island have at least some maroon branches.

Closeup of prickles:

The growing tips of the primocanes are soft, flexible, and weak, with bendy prickles that cannot yet scratch. These growing tips are usually green, not maroon.

The dense covering of hairs gives the plant a frost-dusted appearance at a distance. The hairs catch the light, and make the plant sparkle with a camera flash.

Thickets

Like Himalayan Blackberry, Rubus vestitus can form impenetrable thickets.

Smaller sprawling canes can be found in the shaded understory

Himalayan Blackberry, Rubus bifrons

Note: it is not clear exactly which species our introduced "Himalayan Blackberry" correspond to, and there is a need for genetic studies to clarify this. I refer to them as Rubus bifrons for simplicity, but this could be proven wrong. They are sometimes referred to as Rubus armeniacus. They might even be neither species, or there could be more than one species!

Inflorescence

The pedicels and the branches within the inflorescence are densely covered by white hairs, similar to Rubus vestitus, but they lack stipitate glands.

The sepals are densely hairy, and end in a short point that makes the buds look beaked. On Keats Island, the Himalayan Blackberry tend to have shorter beaks than Rubus vestitus, but I do not know whether this is true of all populations.

The flowers have pale pink to white petals and white stamens. They do not seem to get as dark pink as Rubus vestitus can be.

The petals fall soon after flowering, leaving behind the tangle of stamens.

Floricane: floricane branches

The floricanes are hairy, like Rubus vestitus. This makes it important to determine whether you are looking at a primocane or a floricane before using the hairiness as an ID feature. The hair does seem to be messier and less dense than Rubus vestitus. The colour is variable, from bright green to red.

Floricane: Floricane leaves

Leaves of Himalayan Blackberry are pointier than mature Rubus vestitus leaves, particularly in the terminal leaflet. They may have 1, 3, or 5 leaflets, and vary along the stem. I often see simple leaves (1 leaflet) near the inflorescence, transitioning to 3 and then 5 leaflets farther down the stem, switching back to 3 leaflets near the base of the branch. Leaflet shape is variable, and beware that the leaves at the very base of the stem can be more rounded, similar to Rubus vestitus.

The top of the leaves can be covered in fine hairs. These hairs seem to be much less dense than Rubus vestitus, making them feel less fuzzy. At a distance, the leaves stand out when growing with Rubus vestitus, looking shinier or brighter green, and the veins stand out somewhat less.

The underside (abaxial surface) also has hairs, and prickles along the midvein.

At the base of each leaf is a pair of thin stipules.

Primocanes

The primocanes are much less hairy than Rubus vestitus, making them appear shinier at a distance. If you look very closely, you can still find a few hairs, but they are not as dense as Rubus vestitus.
The primocanes are often green, making them stand out when growing with maroon Rubus vestitus. The colour is variable, however, and the canes can be entirely red, especially when in the full sun. (Rubus vestitus can also be green.)

Primocane Leaves

Primocane leaves are generally divided into five leaflets. The terminal leaflet is pointed, giving it a different shape than the more rounded terminal leaflets of Rubus vestitus.

Thickets

Himalayan Blackberries can also form dense thickets.

On Keats Island, I often find them as just straggling plants among Salal and Rubus vestitus, and they have not started growing within the forest like Rubus vestitus has. There are a few dense thickets in sunny cleared areas.

References

Identifications are based on information in the Flora of North America:
(1) http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100449

All photos are by Else Mikkelsen

Identifying Thimbleberry (R. parviflorus) and Purple-flowered Raspberry (R. odoratus)

Thimbleberry and Purple-flowered Raspberry are two very closely related species that can look quite similar when they are not flowering. Purple-flowered Raspberry (Rubus odoratus) is an eastern species, while Thimbleberry (R. parviflorus) is a western species that can also be found around Lake Superior and Northern Michigan. Where their ranges overlap, the two species might hybridize. Hybrids can also be found in cultivation as Rubus x fraseri.

Purple-flowered Raspberry (R. odoratus)

Key ID mark: sepals

The sepals densely covered in stalked glands that are slightly sticky to touch. These glands are dark purplish, which distinguishes it from its close relative, Thimbleberry, which has glands that are yellowish to reddish (1). The stalks are also longer: in Thimbleberry, these stalks are sessile or no more than 5 times longer than the gland (2). The pedicels and peduncles are also densely covered by glands.

Flowers and fruit

The flowers have 5 petals that are usually deep pink. Occasionally, flowers can have white petals like Thimbleberry - these might be the result of hybrid introgression between the two species (2). Hybrids between the two species are referred to as Rubus x fraseri.

After the petals have fallen, the fruit starts out very pale greenish. Once ripe, it will turn red.

Leaves

The leaves are palmate and large. The tips of the lobes are acuminate, more so than Thimbleberry (2).

The adaxial (upper) surface of the leaves is soft, with short fine hairs.

The abaxial (lower) surface of the leaves is soft and fuzzy, with short fine hairs growing along the veins.

The petiole and the largest veins on the underside of the leaves also have sticky stipitate glands.

At the based of the petioles, there are two thin stipules.

Stems

The young branches are green and with stipitate glands. The older branches are woody with pale brown bark that peels.

Thimbleberry (R. parviflorus)

R. parviflorus can be differentiated from R. odoratus using three key field marks:
1) flowers are white (instead of pink) and are larger than R. odoratus
2) stipitate glands are yellowish/greenish instead of purple
3) Leaves have blunter tips than R. odoratus (less acuminate) but this difference can be subtle

In the above comparison photo, note the difference in flower colour/size and colour of the glands between R. odoratus (left) and R. parviflorus (right).

Flowers

Note the R. odoratus in the background on the left, with noticeable purple stipitate glands.

Stipitate glands

Like R. odoratus, the sepals, young stems, and undersides of the leaves are covered in sticky stipitate glands. These glands are paler than they are in R. odoratus, appearing yellowish or greenish instead of dark purple. Note the dark purple R. odoratus buds in the background of the first and fourth photos here.

Leaves

The leaves are very similar to R. odoratus, but the tips tend to be more blunt, less acuminate than R. odoratus. In these photos, note that there are some purple flowers in the background: those are from an R. odoratus that is growing side-by-side with the R. parviflorus.

Note that young leaves that have not fully expanded can appear more pointed, similar to R. odoratus

Stem

The older stems are woody, like R. odoratus, with peeling bark.

Comparisons

Here are some comparison photos. In this location, a Thimbleberry is growing intertwined with a Rubus odoratus. Even at a distance the difference in colour of the stipitate glands is visible.

Parasites

Rubus can be host to blister rust fungi, which leave powdery orange spots on the leaves

References

(1) http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=128837
(2) MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. June 29, 2022. https://michiganflora.net/species.aspx?id=2560.

All photos are by Else Mikkelsen

This article discusses morphology and identification of the common red and black raspberries in North America: R. idaeus, R. (idaeus) strigosus, R. leucodermis, and R. occidentalis.

Phylogeny preamble

There are many species in the large genus Rubus with the name "raspberry", which generally refers to berries (technically, aggregate fruit) that separate from their receptacle when ripe, giving them a hollowed-out shape (in contrast to blackberries that are not hollow). The commonly cultivated species is Red Raspberry, a familiar sight in supermarkets. Red Raspberries from North America and Europe are often treated as distinct species (R. strigosus and R. idaeus, respectively), but some taxonomies treat them as subspecies (in which case the North American Red Raspberries are R. idaeus strigosus), which is what is currently followed by iNaturalist. Some Red raspberry populations from Asia are also sometimes treated as a separate species, Rubus sachalinensis. The red raspberry lineages are able to interbreed and produce fully fertile hybrids. Plant breeders have worked for centuries to "domesticate" the red raspberry, and many cultivars are now grown commercially in gardens and farms - most of these originate from various crosses between the Eurasian and North American varieties, and many have a bit of ancestry mixed in from other species as well. These hybrid cultivars can frequently be found escaped from cultivation and mingled with the native variety.

Crosses involving red raspberry have also produced other species or commercial crops. Loganberries are a cultivated crop originating from a cross between (European) Red Raspberry and a blackberry (R. ursinus). Similarly, wild Rubus glaucus from the Andes likely originated as a raspberry x blackberry hybrid. Rubus ursinus, a widespread species of western North America, may also be of ancient blackberry x raspberry origin (4).

The closest relatives of the Red Raspberries (apart from their hybrids) are likely the Black Raspberries (4), which consist of at least three widespread species: R. leucodermis in western North America, R. occidentalis in eastern North America, and R. eriocarpus in Central America. Another species, R. nigerrimus, is a rare microspecies restricted to a tiny range in Washington and Oregon that is variably treated as a species or a subspecies of R. leucodermis. R. glaucifolius is another microspecies restricted to a small part of California/Oregon. When present, the colour of the mature berries can easily distinguish red and black Raspberries, but identification is also straightforward with other features when mature berries are absent.

Key field marks to differentiate black and red raspberries

Note: here I am referring to R. occidentalis and R. leucodermis, as "black raspberry" - they are differentiated from red raspberry by the same field marks. They are differentiated from each other by range or by very subtle field marks discussed in their species accounts. I refer to R. idaeus and R. idaeus strigosus as "red raspberry".

When fully ripe berries are present, it can by simple to differentiate the bright red Red Raspberries from the nearly-black purple berries of black raspberries. Unripe berries of black raspberry are red, however, and this frequently leads to them being mistaken for Red Raspberry. Luckily there are some other quick field marks.

The most striking difference is the prickles: black raspberries have strong, curved prickles on their stems. These are shaped like cat's claws and they can hurt or cut if they scratch you. Red Raspberries also have prickles, but these are straight and very thin. As long as you don't grab and squeeze the branches, they won't usually hurt. They are quite weak and are more likely to break than to break your skin (not always...). The best spot to look are the pedicels of the flowers/fruit, where black raspberries have strong prickles, and the common North American variety of Red Raspberry has stipitate glands or very weak straight prickles. European/cultivated varieties of Red Raspberry lack stipitate glands. Cultivated varieties can sometimes have small prickles, but they are not as menacing as black raspberry.

Leaves are also useful: black raspberries usually have only 3 leaflets, and when they have 5 they are arranged palmately, radiating out from a single point. Red raspberries frequently have 5 leaflets, which can be arranged pinnately.

Compare the sharp prickles on the pedicels of black raspberry R. occidentalis (left) to the stipitate glands and weak prickles on red raspberry R. idaeus strigosus (right).

Compare the thick prickles on the 2-year-old (floricane) stems of R. occidentalis (top) to the thin prickles on red raspberry R. idaeus strigosus (bottom)

Compare the palmately arranged leaflets on R. occidentalis (left) to the pinnate arrangement on R. idaeus strigosus (right).

With practice, red and black raspberries can be differentiated at a glance by overall structure. For example, compare these red and black raspberries growing side-by-side: the black raspberries (R. occidentalis, right) have fruit in tighter clusters than the red raspberries (R. idaeus strigosus, left).

Rubus occidentalis

Key field mark: pedicels

The pedicels and peduncles of R. occidentalis are covered by sharp, strong prickles that are curved like cat's claws. Flora of North America suggest that R. leucodermis and R. occidentalis can be differentiated by these prickes: it states that while those on occidentalis are erect, those on R. leucodermis are more often hooked (1).

Flowers

Fruit

The unripe fruits are green.

As they ripen, the fruits begin to turn red, and then become so dark purple that they appear black.

When they are picked or fall off the bush, the fruit (drupelets) easily separate from the torus/receptacle and leave it behind. This gives raspberries their distinctive hollow shape. This distinguishes raspberries with blackberries, in which the fruit is firmly attached to the torus and it stays with the fruit when they are picked (such that the "berries" are not hollow).

Leaves

The leaves of R. occidentalis are deciduous. Each leaf usually has three leaflets (ternate), with a terminal leaflet and a pair of lateral leaflets. The shape of the lateral leaflets is highly variable, even within the same plant. They can be lobed or unlobed, and sometimes divided so deeply that they split in two (pedate), such that the leaf now has 5 leaflets (5-foliate). The apex of the leaflets are described by Flora of North America as acute in R. occidentalis, but acuminate in R. leucodermis, a key ID mark (1) - I believe this is switched around, as the R. occidentalis leaves look quite acuminatae to my eyes!

In these leaves, the lateral leaflets are pedate - they are deeply divided. Some of them are butterfly shaped, and in some of them, they are split so deeply that it looks like they are split into separate leaflets!

The edges of the leaves are toothed or double toothed.

The base of the lateral leaflets holds a key to distinguishing R. occidentalis from R. leucodermis. In R. occidentalis, the leaflets are sessile (that is, they are attached to the stem without a petiolule), while they are described as distinctly stalked in R. leucodermis (1) (but described as subsessile in (3)). With a close view, you can see that the leaf blade of the leaflet starts essentially right where its vein diverges from the pedicel (at least on one side of the vein).

At the base of the leaf, there are a pair of thin (filiform) stipules.

The upperside of the leaves is shiny, without visible hairs.

The underside of the leaves is a pale silvery grey (white-tomentose). The petiolule and larger veins can have small prickles on them. A population of raspberry endemic to a tiny range of Washington/Oregon has leaves that are glabrous, and so the undersides are not silvery. It is not clear whether that population should be considered a subspecies (R. leucodermis nigerrimus) or a separate species (R. nigerrimus) (2)

The leaves near the inflorescence are shaped differently than those on the larger branches. The three leaflets can even be fused into a single leaf.

Stems

Branches in their first year of growth are referred to as primocanes. The primocane stem of R. occidentalis is heavily coated by a waxy substance that gives it a glaucous grey-green colour (pruinose). This is easily rubbed off when touched, revealing a pale green stem beneath. It is armed by strong, decurved prickles that are sparsely distributed. The prickles have a broad base. Thin branches may look pale green with little pruinosity.

Branches in their second year of growth are referred to as floricanes. They are thicker and woodier than primocanes, and brown or purple. They can still be pruinose. Branches sprouting from the floricane bear the flowers and fruits. After the fruiting season, the floricanes die back to make room for the next generation of branches, but the root and crown of the plant are perennial.

Older thickets often have many dried, dead branches from previous seasons. Floricane branches die after they are done fruiting.

Whitebark Raspberry, Rubus leucodermis

Rubus leucodermis is very similar to Rubus occidentalis, but the two species have different ranges: Rubus leucodermis is restricted to western North America and Rubus occidentalis is found farther east.

North American Flora (3) states this:
Rubus occidentalis:

Prickles of the inflorescence scarcely flattened, nearly straight; leaflets dark-green above, abruptly acuminate, with small teeth; stem and branches usually dark bluish-green or purplish, with a bloom.

Rubus leucodermis:

Prickles of the inflorescence strongly laterally flattened and strongly curved; leaflets yellowish-green above, acute or gradually short-acuminate, with coarse teeth; branches often yellowish.

Flora of North America writes this:
Rubus occidentalis:

Lateral leaflets sessile or subsessile; leaflet apices acute; e North America, Great Plains.

Rubus leucodermis:

Lateral leaflets stalked (at least 2 larger ones); leaflet apices acuminate; w North America.

Both mention differences in leaf shape (acuminate vs acute), but the first states that Rubus occidentalis is abruptly acuminate vs acute or gradually short-acuminate in Rubus leucodermis, while the second states that it is Rubus leucodermis that is acuminate and Rubus occidentalis acute! The leaves of Rubus occidentalis that I have seen certainly look acuminate to my eyes, while Rubus leucodermis that I have seen appear more acute and less acuminate in comparison - the key might have a typo unless I have been looking at unusual examples. Compare photos above and below. I have also seen prickles on pedicels of presumed Rubus occidentalis that certainly look curved, so that might not be always reliable. Identifying an out-of-range specimen would probably be difficult. Luckily, their ranges do not overlap... as far as we know!

Flowers

Fruit

Unripe fruits start out green and look similar to Rubus occidentalis. Note that the sepals lack stipitate glands: a related raspberry from California, Rubus glaucifolius, has sepals and pedicels covered by stipitate glands.

Leaves

Leaves are very similar to R. occidentalis, but are described as being more acuminate (I think it is the opposite), and the lateral leaflets are on (very short) petioles. These petioles are very difficult to discern from a distant photo, so it is necessary to get a close look.

The shape of the lateral leaflets is variable, they can be deeply lobed and sometimes these lobes split off into separate leaflets (making the leaves pedately 5-foliate). When this happens, the arrangement of the leaflets is palmate (unlike R. idaeus or R. ursinus in which the arrangement is pinnate).

The undersides are silvery, like other raspberries. There are small prickles on the petiole, petiolule, and midvein.

Stems

Stems are similar to R. occidentalis

Red Raspberry, Rubus idaeus

Key field mark: pedicels

The pedicels of the native variety of red raspberry (R. idaeus strigosus) have a dense covering of stipitate glands. They do not have the strong, curved prickles that black raspberries have, but they may have thin, straight, weak prickles.

Flowers

When the flower is flowering, the sepals are strongly curved backwards. After the petals fall off, the sepals slowly unfurl and bend forwards to encase the developing fruit. This photo shows the progression from bottom to top:

Fruit

Fruits of R. idaeuss are the familiar red raspberries that are grown commercially. They are aggregate fruits, which means that each flower has multiple ovaries, each of which can produce a seed. Each fertilized ovary develops into a drupelet, the segments that cluster together to form the raspberry.

Unripe fruits start out green. They are covered by reddish woolly hairs, which appear dense at first, but become sparse as the fruit expands. When very small, the dense hairs make the green fruits look brownish. The fruit is composed of many segments known as drupelets, and each drupelet has the withered remains of the style and stigma of the ovary, which make the berry look hairy.

Once ripe, the berries are bright red and juicy... and tasty!

Like other raspberries, the fruit is only weakly attached to the receptacle, and the receptacle is left behind when the berry is picked. This differentiates raspberries from blackberries, in which the receptacle stays attached to the berry when it is picked.

Leaves

Unlike R. occidentalis, the leaves usually have 5 leaflets. When they have 5 leaflets, they are generally arranged pinnately, while they are palmate in black raspberry (R. occidentalis/leucodermis.

They can also frequently have only three leaflets, like black raspberry, especially on branches that have flowers.

Sometimes the middle two leaflets are fused to the terminal leaflet.

Like R. occidentalis, the leaflets are sessile.

Like Black Raspberry, the underside of the leaves are silvery. They have fine hairs along the veins, and can have small straight prickles (bristles), especially on the main vein.

Like black raspberry, at the base of the leaves are paired stipules that are very thin (filiform)

Stems

Unlike black raspberries, the stems of R. idaeus lack strong, curved prickles. Instead they have thin, weak, straight prickles (bristles). They can have some bluish wax on the stems, similar to black raspberry, but it usually doesn't make the stems as blue as they can get in black raspberry.

Stems that are older than one year (floricanes) become darker purple/brown and woody. The prickles on these stems are still thin and straight, but they can be more painful (not as painful as black raspberry).

Cultivated red raspberry

Most cultivated red raspberries in North America have ancestry from both European (Rubus idaeus idaeus) and North American (Rubus idaeus strigosus) populations (5). Centuries of breeding have resulted in an overwhelming diversity of named cultivars that have been bred for various traits related to taste, ease of harvest and storage, yield, disease resistance, fruiting time, climate adaptation, and more (5). Plant breeders have also used hybridization to incorporate genetic material from various other species of Rubus into red raspberry cultivars: for example, 'Autumn Bliss' raspberries include influences from Rubus arcticus (5), which is not particularly closely related to raspberries (4). Many modern cultivars have a small amount of ancestry from black raspberry in order to improve the firmness of the berries.

Each domestic cultivar can vary in its appearance, and different cultivars may rise or fall in popularity or be popular in different regions. For example, garden centres near me in Toronto sell 'Heritage', 'Bushel & Berry Raspberry Shortcake', 'Boyne', 'Coho', and 'Meeker' raspberries, but garden centres in colder, hotter, wetter, or drier climates may carry different cultivars. Despite their variation, cultivated raspberries can usually be distinguished from wild Rubus idaeus strigosus by differences in their prickles and glands, especially on the pedicels. While wild red raspberries usually have pedicels with many stipitate glands and a few thin straight bristles, domesticated raspberries can have entirely bare pedicels (lacking stipitate glands), or can have strong curved prickles (resembling Rubus occidentalis but not as menacing). The stems can be entirely smooth and lack prickles, or can have thick triangular prickles (vs. the dense thin bristles of Rubus idaeus strigosus)

Pedicels

This cultivar has thin curved prickles on the pedicels. Note the lack of stipitate glands.

Flowers

Flowers generally look the same as wild red raspberry, except for the lack of stipitate glands on the sepals. Some cultivars have been bred to produce flowers on the first-year (primocane) branches, rather than only on the older second-year (floricane) branches.

Leaves

The leaves are generally similar to wild red raspberry, with 3-5 leaflets and pinnate arrangement. I have seen some with very large leaves.

Leaf undersides:

Look how large these leaves are compared to my hand!

Stems

Some cultivars have robust triangular prickles. They are much stouter than Rubus idaeus strigosus prickles, but not as strong and curved as Rubus occidentalis, and they are red.

This mature bush had stout prickles on the lowest parts of the primocanes, but the rest of the stems lacked prickles entirely and was smooth to touch, with only a few scattered nearly-flat prickles.

This 2-year-old floricane has peeling brown bark and no prickles.

Glossary

Floricane: in gebus Rubus, a branch (cane) that is in its second year of growth, and which can bear the inflorescences (fruits/flowers)
Pedicel: the stalk of an individual flower
Peduncle: the stalk of multiple flowers/fruit (their pedicels attach to the peduncle)
Primocane: in genus Rubus, a branch (cane) that is in its first year of growth
Stipitate gland: glands that are elevated on a thin stalk (stipe)
Ternate: of a leaf, compound with three leaflets

Select References

(1) Flora of North America Vol 9. Rubus leucodermis. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100437
(2) Flora of North America Vol 9. Rubus leucodermis var. nigerrimus. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250100726
(3) Small, John Kunkel. 1905. North American Flora, Volume 22. pg 443-444. https://books.google.ca/books?id=RBolAQAAMAAJ&pg=PA444&lpg=PA444
(4) Carter KA, Liston A, Bassil NV, Alice LA, Bushakra JM, Sutherland BL, Mockler TC, Bryant DW and Hummer KE (2019) Target Capture Sequencing Unravels Rubus Evolution. Front. Plant Sci. 10:1615. doi: 10.3389/fpls.2019.01615
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