488 



ROSACEAE (ROSE FAMILYJ^ 



smooth ; peduncles 1-3-flowered ; petals smalls erects white or pink ; fruit of 

 rather large juicy but acid drupelets. {B. americanus 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. drcticus L. Stems suherect^ 5-20 cm. high, filiform; leaflets 3(-6), 

 Guneate-obovate^ rounded at the tip^ somewhat Jirm, glossy above, coarsely ser- 

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

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

 Minn, (Boreal and Arctic Eurasia.) 



§6. ETIiBATUS Focke. Armed {rarely unarmed) shrubs; stems biennial; 

 leaves on the first yearns growth mostly 6-foUolate (pedate), on the Jtower- 

 ing canes chiefly Z-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 he 

 intergradient and perhaps in some cases hybrid forms. 



, Canes erect or arched-ascending h. 

 &. Pedicels habitually unarmed, often pubescent or glandubr-hispid, 

 rarely with a few weak bristles c. 

 c. Pedicels copiously 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 scarcely 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, weakly armed. 



Fruit of 30-60 small drupelets __ 



Fruit of few large drupelets 13, 



u. Pedicels glandless or with only occasional gland-tipped liairs d. 

 d. Lowersurfaceof leaflets even at maturity downy to the touch e. 

 6. Inflorescence numerously flowered, at length elongated and 

 more or less cylindrical. 

 Inflorescence provided with 4-6 unifoHolate petioled bracts 14. 



9. B. aUeghenienaia. 



12. 



R.flaminanus. 

 R. J-unceua. 



B. glandicatiMa. 

 R. jrondiaeniis. 



Inflorescence with 1-2 unifoliolate petioled bracts 

 e. Inflorescence mostly fewer-flowered, corymbiforui . 



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

 raucroDulate-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 3-5 mm. long 



d. Lower surface of leaflets glabrous, glabrate, or nearly so. 



Internodes of main stem and petioles of 6-foliolate leaves 

 armed with numerous slender or bristle-formsd prickles. 

 Prickles chiefly or exclusively on the angles ; leaflets of the 

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

 Prickles on the faces as well as the 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, subcylindric 



>, Pedicels armed with stoutish or slender but pungent bristle-formed 

 prickles /. 

 /. Leaflets laclniate-cleft ; introduced .... . . 



/. Leaflets not laciniate-cleft (/. 

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



Leaflets whlte-tomentose beneath . . , - 

 Leaflets green or merely grayish beneath. 

 Prickles of the first year's growth rigid. 

 Pedicelff copiously glandular-pubescent . • 

 Pedicels tonientalose but not glandular. 

 Stems rigid, not rooting at the tip; prickles on the 

 first year's growth &-7 mm. long .... 



Stems flexuous, often rooting at the tip; prickles on 

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

 Prickles on the first year's growth numerous, weak, bristle- 

 forflaed, on the surfaces as welJ fts the aiiples of tlie st.ein 



15. 



17. 



19. 



23. 



24. 



25. 



R.frondonus. 

 R. pergrattts. 



B. eaUvus* 

 B. recurvans, 



R. elcgarUulus. 



R. peculiaHs. 



R. Randii. 

 R. canadetisis. 



R. laciniatus. 



R. cuneifoliua. 



R. AndrewsianuA 



R. floricomua. 

 B. Jeckt/7anuf 

 fi. ctbbrevians- 



