482 The Thorn Trees 



stamens about 20; anthers yellow; styles 3 to 5. The fruit ripens in September; 

 it is short-oblong, about 8 mm. thick, dark crimson, becoming black; calyx-lobes 

 reflexed; flesh yellow, succulent, mealy; it contains 3 to 5 nutlets 5 to 6 mm. long, 

 the nest 5 to 7 mm. thick; nutlets ear-shaped, ridged on the back, the inner sur- 

 face roughened with shallow pits. 



51. GREENE'S THORN Crataegus saligna Greene 



Greene's thorn grows on the banks of streams of the continental divide in 

 central and southern Colorado, at altitudes from 2000 to 2500 meters. It is a tree 

 sometimes 6 meters high, with long, spreading, or drooping branches; the bark is 

 reddish-brown, scaly on old trees; the twigs are bright red, smooth, and armed with 

 straight, slender, bright red spines from 5 to 25 mm. long. 



The leaves are thick, rhombic-lanceolate, 1.5 to 5 cm. long, 0.5 to 2 cm. broad, 

 rounded, short, or taper-pointed at the apex on the terminal shoots, wedge-shaped 

 at the base, glandular-toothed with short, flattened teeth, those of the terminal 

 shoots toothed or doubly toothed, shghtly hairy on the upper surface, particularly 



Fig. 441. Greene's Thorn. 



along the veins, smooth beneath, dark green and shining above, paler beneath; 

 leaf-stalks winged towards the top, slightly hairy, about i cm. long. The flowers 

 are about 10 mm. wide, in smooth corj'mbs; calyx-lobes smooth, triangular, pointed, 

 red-tipped; stamens about 20; anthers small, yellow; styles 3 to 5. The fruit 

 ripens in August, is globose, about 8 mm. thick, blue-black, its calyx-lobes re- 

 flexed, persistent; flesh yellow, thin and sweet; it contains 3 to 5 nutlets, commonly 

 5, 3.5 to 4 mm. long, the nest of nutlets 5 to 5.5 mm. thick; nutlets ear-shaped, 

 slightly ridged on the back, with a calyx-scar, inner surface roughened with shallow 

 pits. 



