244 



The Hop Hornbeams 



or, at its northern range, in early June. The clustered staminate catkins are 3 to 

 8 cm. long, their scales triangular-ovate and long-pointed. The ripe pistillate 

 hop-like catkins (strobiles) are oblong, 7 cm. long or less, stalked, the bladder-like 

 bracts 12 to 16 mm. long, pointed, hairy, long-hairy near the base, finely netted- 

 veined; the nut is 5 to 8 mm. long. 



The tree is of rather rapid growth and weU adapted to lawn and park planting. 

 The wood is very strong and tough, close-grained, hard, light reddish brown, 

 with a specific gravity of about 0.83; it is used for tool-handles, mallets, levers, 

 and fence-posts. 



2. KNOWLTON'S HOP HORNBEAM — Ostrya Knowltoni CoviUe 



This is one of the most locally distributed of all trees, being only known to 

 occur in the Grand canon of the Colorado River in Arizona, where it is plentiful 

 at a few places. Trees 10 meters high have been observed with trunks about 



4.5 dm. in diameter near the base; the main 

 trunk is usually very short and divides a little 

 above the ground into several stout, nearly up- 

 right branches, the smaller branches being very 

 irregular and drooping. 



The outer bark is gray and peels off into 

 long thin plates, the inner bark orange-brown. 

 The young twigs are green and very hairy, be- 

 coming smooth, brown, and ultimately light 

 gray. The leaves are small, 5 cm. long or less, 

 ovate to oval or obovate, blunt or short-pointed, 

 sharply doubly toothed, rounded or shghtly 

 heart-shaped at the base, finely hairy on both 

 sides, rather dark green above, paler beneath; 

 the very hairy leaf-stalks are 2 to 6 mm. long. 

 The flowers appear in May. The staminate 

 catkins are 2 to 3 cm. long, their scales broadly 

 ovate and rather abruptly pointed. The ripe pistillate catkins are about 3 cm. 

 long, stalked, with fewer bladder-Kke bracts than those of the eastern tree; the 

 nut is about 6 mm. long. 



The wood is hard, close-grained, and light reddish brown. 

 Bailey's Hop hornbeam {Ostrya Baileyi Rose) recently described from the 

 Guadalupe Moimtains, Texas, differs in the more glandular petioles and darker 

 brown tvngs. It is only known from meager specimens, and its fruit is as yet 

 undescribed. 



Fig. 2oy. — Knowlton's Hop Hornbeam. 



