488 



KOSACEAE (rose FAMILY) 



smooth ; peduncles 1-3-flowered ; petals small, erect, white or pink ; fruit of 

 rather large juicy but acid drupelets. (B. americanns Britton.) — Wet woods, 

 etc., Lab. to Alaska, south w. to N. J., the Great L. region, n. la., and Neb. — 

 Sepals and petals often 6-7. 



8. R. arcticus L. Stems suherect, 5-20 cm. high, filifonn ; leaflets 3(-5), 

 cuneate-obovate, rounded at the tip, somewhat firm, glossy above, coarsely ser- 

 rate-dentate ; petals rather large, spreading, rose-colored (rarely white) ; fruit 

 as in the preceding. — Boggy places, Arctic Am., south w. to e. Que. and n. 

 Minn. (Boreal and Arctic Eurasia.) 



§ 5. eCfBATUS Focke. Armed {rarely unarmed) shrubs; stems biennial; 

 leaves on the first year'^s growth mostly o-foliolate (pedate), on the floicer- 

 ing canes chiefly '-^t-foliolate ; fruit not separating from the juicy receptacle, 

 blackish when ripe {reddish in no. 34). Blackberry. — A group of great 

 taxonomic difficulty, in which many species have been recently proposed. 

 Of these, the better marked have been here freely included, but without 

 entire confidence that future intensive study may not show them to be 

 intergradierit and perhaps in some cases hybrid forms. 



a. Canes erect or arched-ascending b. 



b. Pedicels habitually unarmed, often pubescent or glandular-hispid, 

 rarely with a few weak bristles c. 

 c. Pedicels copioush- glandular-hispid. 



Leaflets appressed-villous above ; prickles of the stem stoutish 

 Leaflets glabrous above ; prickles of the stem setiform rather 

 than thorn-like. 

 Petioles of the 5-foliolate leaves scarcelj"^ or not at all glandu- 

 lar, copiously armed with hooked prickles ; leaflets rhom- 

 bic-lanceolate or narrowly ovate. 

 Lower surface of the leaflets velvety to the touch 

 Lower surface of the leaflets essentially glabrous . 

 Petioles of the 5-foliolate leaves copiously glandular-pubes- 

 cent, weaklj' armed. 



Fruit of 30-60 small drupelets 



Fruit of few large drupelets 



c. Pedicels glandless or with only occasional gland-tipped hairs d. 

 d. Lower surface of leaflets even at maturitj- down}- to the touch e. 

 e. Inflorescence numerously flowered, at length elongated and 

 more or less cylindrical. 

 Inflorescence provided with 4-6 unifoliolate petioled bracts 

 Inflorescence with 1-2 unifoliolate petioled bracts 

 e. Inflorescence mostly fewer-flowered, corymbiform. 



Canes erect or nearly so ; teeth of the leaflets deltoid-ovate, 

 mucronulate-acuminate ; prickles of stem few, weak, 



1-2 mm. long 



Canes commonly recurved and often rooting at tip ; teeth 

 of leaflets lanceolate, narrowly acuminate ; prickles of 



stem mostly -i—b mm. long 



dm Lower surface of leaflets glabrous, glabratc, or nearly so. 



Internodes of main stem and petioles of 5-foliolate leaves 

 armed with numerous slender or bristle-formed prickles. 

 Prickles chiefly or exclusively on the angles ; leaflets of the 

 mature 3-foliolate leaves small, rarely over 5 cm. long . 

 Prickles on the faces as well as ttio angles of the stem ; leaf- 

 lets of the 3-foliolate leaves larger, often 6-8 cm. long . 

 Internodes and petioles with few prickles or unarmed. 



Inflorescence corymbiform ....... 



Inflorescence racemiform, subcyhndric 



b. I'edicels armed with stoutish or slender but pungent bristle-formed 

 prickles /. 



/. Leaflets laciniate-cleft ; introduced 



f. Leaflets not laciniate-cleft ff. 

 g. Lower surfaces of the leaflets velvety to the touch. 



Leaflets white-tomentose beneath 



Leaflets green or merely grayish beneath. 

 Prickles of the lirst year's growth rigid. 

 Pedicels copiously glandular-pubescent 

 Pedicels tomentulose but not glandular. 

 Stems rigid, not rooting at the tip ; 

 first year's growth b-~ mm. long 

 Stems flexuous, often rooting at the 

 the first year's growth 2—5 mm. long 

 Prickles on the first year's grov.-th numerous, wcjik. bristle- 

 formed, on the >iirfa('»'s lis well as the angU-s nt thr stt-in 



prickles on the 

 tip ; prickles on 



9. R. allegh&niensii. 



10. R.flavinamui. 



11. R.junceus. 



12. R. glandicaulia. 



13. R.frondisentis. 



14. R.frondofius. 



15. R. pergratxts. 



16. R. sativus. 



18. 



19. 



20. 

 21. 



25. 



26. 



/ 



17. R. recurvans. 



R. elegantulua. 



R. peculiaria. 



R. Randii. 

 R. canadensis. 



22. /?. lacinintus. 



23. R. cuneifolius. 



24. li. AndreicsianuA 



R. floricomu«. 

 li. .JeckyJanu* 

 A*, (ihhrerians. 



I 



