Howell's Thorn 



475 



calyx-lobes triangular; stamens about 20; anthers red; styles 3 to 5. The fruit 

 ripens late; it is globose to subglobose, red, 4 to 6 mm. thick, calyx-lobes reflexed; 

 flesh dry and mealy; it contains 3 to 5 nutlets, 3 to 3.5 cm. long, the nest 3.5 to 

 4.5 mm. thick, the calyx-scar conspicuous. 



41. ENGELMANN'S THORN Crataegus brachyacantha Engelmann and 



Sargent 



Engelmann's thorn grows in moist soil in southern Arkansas, Louisiana, and 

 Texas. It is a tree sometimes 15 

 meters high, with spreading 

 branches, forming a round-topped 

 crown; the bark is dark brown, 

 deeply furrowed; the twigs are 

 reddish brown, smooth, and are 

 armed with curved spines i to 2 

 cm. long, and the ends of the 

 branches often terminate in spines. 



The leaves are oblanceolate- 

 elliptic or narrowly ovate, 2.5 to 

 5 cm. long, I to 2.5 cm. wide, 

 pointed or rounded at the apex, 

 wedge-shaped decurrent below, 

 crenate-toothed, smooth, half- 

 leathery, dark green and shining 

 above, paler beneath, the veins 



Fig. 431. Engelmann's Thorn. 



not very conspicuous; leaf-stalks narrowly wing-margined above, i to 2 cm. long. 

 The flowers are about 10 mm. wide in smooth, many-flowered cor^'mbs; calyx- 

 lobes short-pointed; stamens 15 to 20; styles 3 to 5. The fruit ripens early; it 

 is subglobose, about 10 mm. thick, blue-black, with a glaucous bloom; calyx- 

 lobes spreading; flesh thin; it contains 4 or 5 nutlets 5 to 6.5 mm. long, the nest 

 5.5 to 8 mm. thick. 



42. HOWELL'S THORN Crataegus columbiana Howell 



Howell's thorn occurs commonly along the tributaries of the Columbia River, 

 east of the Cascade Mountains, and extends east to central-northern North Dakota, 

 and north into British Columbia. It is a much-branched shrub or small tree, 

 sometimes 5 meters high; the twigs are reddish brown, smooth, and bear some 

 chestnut-brown spines from 2 to 6 cm. long. 



The leaves are thin, wedge-shaped, ovate or oblong, 2 to 6 cm. long, i to 5 cm. 

 wide, with 3 or 4 pairs of sharp lobes, the lower pair often quite deeply cut, sharply 

 and finely doubly toothed, sparingly long-hair}-, particularly along the veins; leaf- 



