112 ROSACEAE 



are oval, less acuminate, and 'I1/4 to 4 inches long. The flowers 

 occur in lax racemes commonly 3 to 6 inches long, at the tips 

 of branches and in the axils of old leaves. The oval petals are 

 about 1/2 inch long and the lanceolate sepals are acuminate. 

 The flowers, which blossom in May and June, develop later 

 into black and very pulpy fruits about Yi inch long. 



Distribution. — This blackberry inhabits thickets and w^oods 

 and grows from Newfoundland west to IVIinnesota and south- 

 ward as far as North Carolina. In Illinois, it is a rare shrub 

 reported definitely only from Cahokia, south of East St. Louis. 

 Possibly this report is erroneous. 



RUBUS ARGUTUS Link 

 Highbush Blackberry Tall Blackberry 



The Highbush Blackberry, fig. 25, is an erect or somewhat 

 nodding shrub with canes that when old reach a length of 3 

 to 6 feet and have at least the upper part deeply furrowed and 

 prickly. It is characteristic that the prickles are flattened at 

 the base. They are straight or recurved, the recurved ones 

 more abundant toward the tip of the stems. The new canes, 

 which usually are smooth but sometimes pubescent or sprinkled 

 with sessile red glands, are deeply channeled on the sides. The 

 leaves of new canes are usually 5-foliate. Terminal leaflets are 

 acuminate at the apex, rounded or subcordate at the base and 

 generally about 3 inches long by II/2 Inches wide. The blade is 

 slightly pubescent above and definitely pubescent beneath, espe- 

 cially along the veins. The margins are more or less doubly and 

 sharply serrate. The leaves of old canes are almost entirely 

 3-folIate, with leaflets similar to those on the new canes, except 

 that they are smaller and are gradually rather than abruptly 

 acute at the apex. 



The inflorescence Is a short raceme, consisting commonly of 

 6 to 10 flowers. Its peduncle pubescent and armed more or less 

 with recurved prickles. It may be terminal or arise from the 

 axils of leaves. The white flowers, which bloom in the early 

 part of June, have round to oval petals about 1/ inch long and 

 ovate sepals with abrupt tips, which are strongly reflexed at 

 fruiting time. The pedicels of the flowers are strongly ascend- 

 ing, about Yi to 1 inch long, pubescent, and sometimes prickly. 

 Fruit ripens from late July to about the middle of August. It 



