Rubus Rosaceae 557 



Plants normally slender, relatively short or else comparatively weak and 

 often with an herbaceous appearance, the bases of young primocanes 

 bearing scalelike caducous bracts; leaves thin and soft; primocane 

 leaflets usually 3; flowers mostly solitary, large, long-pediceled, with 

 large tomentose calyx lobes, reflexed at full anthesis ... 8. R. Enslenii. 

 Pedicels with stalked glands. 



Primocanes glandless, with 3-foliolate leaves, prickles small, few, and of 

 equal size; leaflets soft-pubescent beneath; leaves of floricanes similar 

 to those of the primocanes but less tomentose beneath, prickles small, 

 few, sometimes the stem nearly unarmed; flowers few, 3-5, on upright 



pedicels; calyx lobes ascending 9. R. centralis. 



Primocanes usually with stalked glands (sometimes without them) and 

 with prickles of two sizes and about 5 per cm; leaves 3-5-foliolate ; 

 floricane with two kinds of prickles and with scattered, stout glands, 

 flowers mostly 6 or fewer on elongate pedicels which are prickly and 

 glandular; petals elliptic; whole plant much more armed than the 



preceding 10. R. Deamii. 



Floricanes erect, ascending or arching (rarely diffuse). (Blackberries.) 



Canes erect or diffuse, glabrous, unarmed or with a few, widely scattered, weak 

 prickles. 



Canes erect. (See excluded species no. 349, p. 1061.) R. canadensis. 



Canes diffuse. (See excluded species no. 350, p. 1061.) 



R. canadensis var. Randii. 



Canes ascending or arching (at least the floricanes), well armed with stout 

 prickles and more or less pubescent or glandular or both. 

 Inflorescence and petioles bearing many prominent glandular hairs; char- 

 acteristic well developed flower-clusters long-racemiform with continuing 

 axis; pedicels (except the basal ones) strongly divaricate. 

 Axis of well developed flower-clusters long and open, without interspersed 

 foliage, the leaves being only at the base of the cluster; rachis prom- 

 inently continuous and pedicels divaricate 11. R. allegheniensis. 



Axis of well developed flower-clusters leafy and shorter. Bailey says, in 

 comparison with the preceding species, that it "lacks the narrow long- 

 stalked leaflets, is less glandular, canes more terete and lacking the 

 strong angles, broad-petaled flowers on very long slender pedicels (at 

 least the lowest flowers in cluster) subtended by prominent outstanding 



bracts." 12. R. impos. 



Inflorescence, petioles and other parts not bearing prominent glandular hairs, 

 if glandular hairs are present, then few and not very large; flower-clusters 

 various, but not long-racemiform as a rule. 

 Main flower-clusters standing well above the foliage and of the short- 

 racemiform type with many flowers; floral leaves mainly at or near 

 the base, the plant therefore representing a floriferous rather than 

 a leafy appearance; flowers of medium size to small, with narrow petals 

 (except in R. pergratus), spreading in anthesis. 

 Primocane leaflets of the oblong or narrow order and not cordate, some- 

 times small, mature leaves likely to have prominent, closely parallel 

 side-veins; inflorescence not characteristically of the long-racemiform 

 type. 



Inflorescence interspersed with prominent simple leaves 



13. R. laudahis. 



Inflorescence without prominent simple leaves. 



Leaflets of primocanes narrow, of a broad-lanceolate or ovate- 

 lanceolate order, with curved, tapering sides, only thinly pubes- 

 cent beneath; flower-clusters on unarmed pedicels or bearing 

 only a few, weak prickles; plant not very prickly.. .14. R. argutus. 



