356 BOTANY OF CROP PLANTS 



four principal groups of dewberries, which are distinguished 

 in the following key : 



Key to Principal Species of Dewberries 



Leaves evergreen, R. trivialis (southern dewberry). 

 Leaves deciduous. 



Buds tipped by the united ends of the sepals, forming a spine; flower clus- 

 ters forking into two or three parts, R. invisus (northern dewberry). 

 Buds not tipped by the united ends of the sepals to form a spine. 

 Both hermaphrodite and pistillate plants; leaflets coarsely toothed, R. 



miif alius (western dewberry). 

 Plants all perfect; leaflets finely toothed, R. villosus (northern dewberry). 



Rubus trivialis. — These are trailing shrubs, with stout, hooked prickles and 

 bristles on the stems, and with upright branches 3 to 9 inches tall. The leaves 

 are trifoliate, petioled, and with oval, leathery, serrate, evergreen leaflets. 

 The inflorescences are one- to five-flowered. The flowers are large, white, 

 and have petals that are much longer than the sepals. The fruit is black, 

 and up to i inch long. The species occurs from Virginia to Florida and west- 

 ward to Texas and Missouri. The best-known horticultural variety is 

 Manatee. 



Rubus invisus. — The stems are moderately prickly. The leaflets are large 

 and coarsely and simply dentate. The erect peduncles are elongated. The 

 large flowers are on long pedicels; flower buds are tipped by the united ends 

 of the sepals. The species is reported by Bailey as growing wild from New 

 York to Alabama and east to Kansas and Missouri. The chief varieties are 

 Bartel and Mammoth. 



Rubus vitifolius. — This species occurs in California, Oregon, Washington 

 and Idaho. Skagit Chief is the principal form in cultivation. 



Rubus viUosus.^The plants are robust, with smooth stems and large, 

 thick leaves, which have three to seven oval or ovate, long-pointed and sharply 

 double- toothed leaflets. The inflorescences are one to three-flowered, leafy, 

 and cymose. The fruit is globular, and has a few, shining-black, and sweet 

 drupelets. This is the common dewberry of the Northern States; it is found 

 growing wild from Newfoundland to Virgina and westward to Minnesota and 

 Kansas. Windom, Geer and Lucretia's Sister are varieties. The Lucretia 

 dewberry (variety roribaccus) is a more robust form with large wedge-obovate, 

 jagged leaflets, and large flowers on long pedicels. 



