60 THE EVOLUTION OF PLANTS 



Dioon, and Microcycas (fig. 4), are American, the 

 last-named, containing a single species, having 

 only been found in the island of Cuba. The 

 family is thus widely distributed, though its 

 members are not often met with in great abund- 

 ance. 



In a few cases the living Cycads attain the 

 stature of trees. Microcycas (in spite of its name, 

 which means little Cycad) grows to a height of 

 SO feet; a species of Dioon, from Mexico, attains 

 40 feet, and an Australian species of Cycas is 

 said to reach as much as 60 feet in height. Some 

 species of Encephalartos, when old, have the 

 character of low trees. In most species of the 

 family, however, the stems, though long-lived 

 and often massive, remain short. 



In nearly all cases the leaves, which are al- 

 ways of considerable size, are simply pinnate, 

 the midrib bearing two rows of leaflets; in the 

 Australian Bowenia the leaflets are again divided 

 in the same way, and in a species of Cycas re- 

 cently discovered in Annam, each leaflet is forked 

 twice or more. The leaves of the African Stan- 

 geria (fig. 1) are veined exactly like those of a 

 Fern, so that the plant was described as a Fern 

 of the genus Lomaria when first brought to Eng- 

 land, and its true nature was only revealed when 

 its cones appeared. Another Fern-like feature 

 in some Cycads is the way the leaves are coiled 



