Key to Rubus

View taxon page for Rubus

(For a list of species in Rubus, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Stipules triangular-lanceolate to 

ovate 

Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf.

or 

elliptic 

In the shape of a flattened circle or ellipse; wider than linear

, 1.5–4(10) mm wide

2. Prickles small, ± wide-based, curved ..... R. nivalis

2' Prickles 0

3. Stems 

prostrate 

Lying flat on the ground.

; 

leaf 

Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).

 

blade 

Expanded portion of a leaf, petal, or other structure, generally flat but sometimes rolled, cylindric, wavy, or cupped.

< 4 cm; pistils < 15; styles long, slender ..... R. lasiococcus

3' Stems 

erect 

Upright; vertically oriented.

; leaf blade > 5 cm; pistils > 30; styles short, thick ..... R. parviflorus

1' Stipules thread-like to 

linear 

Elongate, with nearly parallel sides; narrower than elliptic or oblong.

, <= 1 mm wide

4. Stems not angled; flowers generally <= 10; fruit raspberry-type (blackberry-type in Rubus ursinus)

5. Stems erect, not glaucous; petals magenta ..... R. spectabilis

5' Stems prostrate to 

decumbent 

lying mostly flat on the ground but with tips curving up.

or arched to mounded, glaucous; petals white or ± pink

6. Leaves gray-hairy abaxially; flowers generally unisexual; ovaries glabrous or hairy ..... R. ursinus

6' Leaves densely white-tomentose abaxially; flowers 

bisexual 

Both male and female reproductive parts occurring and functional in the same plant or structure (e.g., flower, spikelet, inflorescence).

; ovaries densely hairy

7. Prickles weak, straight or ± curved; pistils < 10 ..... R. glaucifolius

7' Prickles stout, straight or generally curved; pistils generally > 30 ..... R. leucodermis

4' Stems 5-angled; flowers generally >= 10 (as few as 5 in Rubus pensilvanicus); fruit blackberry-type

8. Prickles 0 ..... R. ulmifolius var. anoplothyrsus

8' Prickles many, stout, wide-based

9. Leaves compound, leaflets deeply dissected ..... R. laciniatus

9' Leaves 

simple 

Composed of a single part; undivided; unbranched.

or compound, leaflets 0 or not dissected

10. Leaves gray-hairy abaxially; inflorescence a raceme-like 

cyme 

1. In flowering plants excluding Asteraceae and some other groups, a branched inflorescence in which the central or uppermost flower opens before the peripheral or lowermost flowers on any axis. see 2. In Asteraceae and some other groups, a cyme-like inflorescence is one in which the central or uppermost inflorescence units (e.g., heads in Asteraceae, umbels enclosed by involucres in Eriogonum), instead of individual flowers, develop and mature before the peripheral or lowermost inflorescence units on any axis.

..... R. pensilvanicus

10' Leaves densely white-tomentose abaxially; inflorescence a panicle-like cyme

11. Stems not glaucous; terminal leaflets of 1st-yr stems generally wide-elliptic to -obovate, unevenly coarse-toothed ..... R. armeniacus

11' Stems glaucous; terminal leaflets of 1st-yr stems 

oblong 

Longer than wide, with nearly parallel sides; wider than linear.

to narrow-obovate, evenly finely toothed ..... R. ulmifolius var. ulmifolius

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