GNETALES— EPHEDRA 



365 



near Tehuacan, Mexico, is usually about 30 cm. in height, and sel- 

 dom reaches 50 cm. On the other hand, the stem of the South 

 American E. triandra sometimes reaches a diameter of 30 cm. and a 

 height of several meters. What the age of these large plants might 

 be has not been determined. Land^^^ reported 40 rings in an old 

 plant of E. trifurca. Since this is the largest number of rings reported 

 for any species. Ephedra is a short-lived plant. 



Fig. 346. — Ephedra trifurca: transverse section of part of stem about i cm. in diam- 

 eter, showing numerous vessels of various sizes. The largest vessels are formed earlier 

 in the season, as may be seen from the vessels above the growth-ring. A large medul- 

 lary ray is shown in the middle of the figure; X170. 



Branching begins very early, buds appearing even in the axils of 

 the cotyledons. In older plants the first branches are often covered 

 by soil (fig. 345) . When the soil is loose, and conditions are favorable, 

 buds at the nodes may grow out into long rhizomes, and buds on 

 the rhizomes may develop into new plants. Land^''° found numerous 



