The Tremas 



359 



Fig. 318. Heller's Hackberry. 



least above the middle, mostly heart- 

 shaped at the base, dark green and very 

 rough on the upper surface, finely gray- 

 haiiy on the lower and rather strongly 

 netted-veined ; their stout stalks vary from 

 3 to 10 mm. in length. The fruit is nearly 

 globular, 7 to 10 mm. in diameter, light 

 brown and shining, its curved stalk i to 

 1.5 cm. long. 



9. DOUGLAS' HACKBERRY 

 Celtis Douglasii Planchon 



This tree inhabits river valleys in Idaho, 

 Oregon, Washington, and British Columbia, 



south to Utah and Colorado, and much re- 

 sembles the Thick-leaved hackberry of the 

 southwest, with which it has been confused, 

 and it is also closely related to the eastern 

 Celtis occidentalis. It attains a height of 

 about 7 meters, but is usually lower, and 

 commonly a mere shrub. 



The bark is bright brown and rough, the 

 young twigs hair}\ The leaves are ovate to 

 ovate-lanceolate, 10 cm. long or less, pointed, 

 often long-pointed, rough above, rather 

 strongly netted-veined beneath; their stalks 

 are hairy and short, usually not more than 

 6 mm. long. The flower-stalks are slen- 



_,,-,,, der, equaUing or ^ or 4 times as long as the 



Fig. 319. Douglas Hackberry. 7 n o ^ -r o 



leaf-Stalks, and loosely hair}^ The globular 

 fruit is about 8 mm. in diameter and black when ripe. 



IV. THE TREMAS 



GENUS TREMA LOUREIRO 



HIS genus contains about 30 species of unarmed trees and shrubs, 

 natives of tropical regions. The one here described occurs only in 

 southern Florida, so far as is known. T. micrantha (Swartz) Blume, 

 is abundant on Porto Rico and other West Indian islands, and in Cen- 

 tral America; T. Lamarckiana (Roemer and Schultcs) Blume, occurs on the Ba- 

 hamas, Cuba, and Santo Domingo to Montserrat and Guadalouj)c; T. mollis 



