RUBUS 121 



N. J., Pa., the Great Lake region, northern Iowa, Ariz., Cal. and Eurasia. 

 Flowers and fruits from June to Sept. 



Rubus L i n ne 1753 Bramble, Blackberry, Raspberry 



(L. rubus, bramble, akin to ruber, red) 



Erect or procumbent shrubs or trailing vines, frequently prickly, with 

 alternate simple, lobed, or 3-7-foliate leaves; flowers white (sometimes 

 pink or purple) ; calyx flat, 5-parted, persistent; petals 5, deciduous; 

 stamens numerous ; carpels usually many, borne on a spongy or succulent 

 receptacle, ripening into drupelets and forming an aggregate fruit, edible. 



A genus of about 250 species, of wide geographical distribution, but 

 most abundant in the north temperate zone. About 20 species in addition' 

 to the following occur in North America. 



Key to the Species. 



1. Leaves simple, palrriately lobed; stems unarmed R. parvi ' floras 



2. Leaves compound, 3-7-foliate; stems prickly or 



bristly 



a. Fruit falling off whole from the dryish re- 



ceptacle when ripe Raspberries 



( 1 ) Stems upright, beset with straight, stiff 



bristles ; fruit red 



(a) Calyx bristly-hispid, with slender 



prickles; native R, strigosus 



(b) Calyx not bristly-hispid, woolly- 



pubescent; cultivated R. idaeus 



(2) Stems recurved, rooting at the tips, 



armed with hooked prickles; fruit 



purple-black R. occidentalis 



b. Fruit not separating from the juicy receptacle 



when ripe Blackberries 



( 1 ) Stems trailing or at least prostrate to- 



wards the ends; fruiting branches up- 

 right R. villosus 



(2) Stems erect or arched ascending 



(a) Old stems unarmed or nearly so; leaf- 



lets glabrous on both sides R. canadensis 



(b) Old stems purplish and ar-med with 



stout prickles R. allegheniensis 



