Rough-Leaved Thorn 



477 



and sweet when mature; it contains 4 or 5 nutlets 6 to 7 mm. long, strongly ridged 

 on the back, with a shallow pit on each inner face, the nest 7 to 8 mm. thick. 



44. PRAIRIE THORN — Cratsegns pertomentosa Ashe 

 CratcBgus campestris Britton 



s 



This species is found in rocky barrens from western Missouri and eastern Kan- 

 sas to central Iowa. It is a tree sometimes 5 meters high, with nearly horizontal 

 branches, forming a flattened 

 crown; the bark is dark gray; 

 the twigs are reddish brown, 

 hairy, soon becoming smooth 

 and armed with numerous chest- 

 nut-brown curved spines from 3 

 to 9 cm. long. 



The leaves are oblong to 

 ovate, 3 to 7 cm. long, 2 to 6 

 cm. wide, sharply and finely 

 doubly toothed, with 4 or 5 pairs 

 of small abruptly sharp-pointed 

 lobes, pointed at the apex, 

 broadly wedge-shaped or 

 rounded at the base, slightly 

 long-hairy above, particularly 

 along the veins when young, be- 

 coming smooth, hairy beneath, more thickly along the veins, half leathery, bright 

 dark green above, paler beneath; leaf-stalks about i cm. long, winged, shghtly 

 hairy, glandular. The flowers are about 2 cm. wide, in many-flowered densely 

 long-hairy corymbs; calyx-tube densely long-hairy, the lanceolate long-pointed 

 lobes deeply toothed, with glandular tips, hairy on the inside, nearly smooth 

 without; stamens 10 to 15; styles 2 or 3. The fruit, ripening in September, is 

 8 to 13 mm. thick, round, cherry-red, hairy when young; flesh yellow, succu- 

 lent, becoming mealy when mature, epclosing 2 or 3 nutlets 5 to 6.5 mm. long, 

 ridged on the back and pitted on the inner face, pits varying from shallow 

 to deep and occasionally wanting on individual nutlets, the nest of nutlets 5 to 

 6.5 mm. thick. 



Fig. 434. — Prairie Thom. 



45. ROUGH-LEAVED THORN — Oratagus asperifolia Sargent 



CrattBgus Deweyana Sargent. Cratmgus McGeem Ashe 



This thorn occurs from western Nova Scotia to Iowa. It is a tree sometimes 8 

 meters high, with the lower branches horizontal and the upper ones ascending, 



