GENUS 28. ROSE FAMILY. 275 



28. RUBUS [Tourn.] L. Sp. PI. 492. 1753. 



Perennial herbs, shrubs or trailing vines, often prickly, with alternate simple lobed or 

 3-7-foliolate leaves, the stipules adnate to the petiole. Flowers terminal or axillary, solitary, 

 racemose or panicled, white, pink or purple, perfect or sometimes dioecious. Calyx persistent, 

 not bracted, deeply 5-parted, its tube short and broad. Petals 5, deciduous. Stamens o, 

 usually numerous, inserted on the calyx, distinct. Carpels o, rarely few, inserted on a 

 convex or elongated receptacle, ripening into drupelets and forming an aggregate fruit, 

 which in many species is edible, sweet and delicious, in others sour, or nearly tasteless. 

 Ovules 2, one abortive. Style nearly terminal, slender. Seed pendulous. [The ancient 

 name of the bramble, from ruber, red.] 



Perhaps 200 species, of wide geographic distribution, most abundant in the north temperate 

 zone. Besides the following, several others occur in North America beyond our area. A great 

 many species, based mainly on trivial characters of pubescence, habit and leaf-form have been 

 described since the publication of our first edition ; many of these are hybrids between the different 

 blackberries and others are races. There is great difference of opinion, both in Europe and Amer- 

 ica, regarding the number of valid species. All the British brambles were reduced to a single 

 species, R. fruticosus L., by Bentham, but other authors have recognized and described a large 

 number. The stems of many species are biennial. Several species are widely cultivated for their 

 edible fruits, which have been improvd by selection. Type species : Rubus fruticosus L. 



Leaves simple, crenate or palmately lobed. [Genus RUBACER Rydb.] 

 Shrubby, 2-5 high, branched ; flowers corymbose. 



Flowers numerous, red-purple. i. R.odoratus. 



Flowers few, white ; western. 2. R. parviflorus. 



Herbaceous, S'-Q' high, simple ; flowers solitary, white. 3. R. Chamaemorus. 



Leaves 3-7-fpliolate (rarely simple in a race of No. 4). 



Fruit falling away from the dry receptacle. RASPBERRIES. 



Stems bristly, not glaucous ; fruit light red. 4. R. strigosus. 



Stems prickly, slightly glaucous ; fruit dark red. 5. R. neglectus. 



Stems prickly, very glaucous ; fruit normally purple-black. 6. R. occidentalis. 



Fruit persistent on the fleshy receptacle. BLACKBERRIES. 

 Herbaceous, unarmed ; fruit red to purple. 



Erect, 10' high or less ; petals obovate, usually pink. 7. R.arctictis. 



Trailing or ascending ; petals spatulate-oblong, white. 8. R. triflorus. 



Shrubby, usually bristly or prickly ; fruit black when ripe. 



Leaves White-woolly beneath ; stems erect or nearly so. 9. R. cuneifolins. 



Leaves not white-woolly beneath. 



Stems erect, ascending, or arching. 



Unarmed, or with very few distant prickles ; leaves glabrous on both sides. 



10. R. canadensis. 

 More or less densely prickly, or bristly. 



Leaves glabrous on both sides. n. R.nigricans. 



Leaves velvety-pubescent beneath. 



Inflorescence with few or several unifoliolate leaves ; fruit subglobose. 



12. R.frondosus. 

 Inflorescence not leafy ; fruit oblong to cylindric. 



Pedicels without prickles. 13. R.alleghanensis. 



Pedicels prickly. 14. R.argutus. 



Stems trailing or procumbent. 

 Leaves dull above ; fruit black. 

 Leaves deciduous. 



Leaflets pubescent beneath, mostly rounded or cordate at base. 



15. R.Baileyanus. 



Leaflets glabrous or nearly so, mostly narrowed at base. 16. R. procumbent. 

 Leaves coriaceous, persistent. 1 7- R- trivialis. 



Leaves shining above ; fruit reddish. 18. R. liispidus. 



