6 



Gnetaceae. 



Ephedra. Canatillo. 

 (Family Gnetaceae). 



Scraggly shrubs. Twigs green, 

 finely striate and usually granular, 

 elongated, straight and slender: 

 pith round, red-brown, resinous, 

 continuous except for firm pale 

 diaphragms at the nodes. Buds 

 solitary, sessile, ovoid, small, with 

 about 3 pairs or whorls of scales 

 or the flower-buds collaterally mul- 

 tiple and developing into large 

 thin-scaled "cones" in fruit. Leaf- 

 scars and stipule-scars lacking. 

 Leaves reduced to scarious scales, 

 connately opposite or whorled. 



The heterogeneous family Gneta- 

 ceae, represented here by Ephedra, 

 though now considered to belong 

 to the group of Gymnosperms was 

 long held to be angiospermous, and 

 it combines the characters of these 

 superior groups in so puzzling a 

 way that its present taxonomic location is more tenable on 

 grounds of embryogenesis than for other reasons. Like the 

 Angiosperms, its secondary wood produces true vessels, the 

 other Gymnosperms containing tracheids only. 



1. Leaf-scales opposite in pairs, ovate, brown, soft. 2. 

 Leaf-scales in whorls of three. 3. 



2. Scales very short (1-2 mm.). E. viridis. 

 Scales moderate (4-5 mm.), sheathing. E. antisyphilitica. 



3. Scales short (3 mm.), soft. E. Torreyana. 

 Scales elongated (10 mm.), subpungent. E. trifurca. 



