1-6 



THE PSILOTACE/E 



absorbing its nourishment from decaj-ing plant tissues by 

 means of its root-like rhizomes. These rhizomes are curi- 

 ous structures consisting of a great number of cord-like 

 organs that form a tangled mass from six inches to a foot 

 or more in extent. From various parts of the rhizome 

 the stems rise to a height of twelve inches or more, at the 

 top forking repeatedly to form the fan-shaped branches. 

 The base of the main stem is about one tenth of an inch 

 in diameter and is three-angled, and the branchlets are 

 three-winged. The leaves are reduced to tiny linear 

 scales less than one twelfth of an inch long, and, though 

 scattered along- the angles of the stems 

 and branches, are so inconspicuous that 

 the plant always appears to be leafless. 



The sporangia occur singly along the 

 branchlets, each small leathery spore-case 

 held in a slight hollow of the stem by a 

 forked sporophyll which looks like a pair 

 of the stem leaves. The spore-cases are 

 globular or top-shaped, three-lobed, three- 

 celled affairs, opening at the top, when 

 ripe, by three tiny oblong slits. Spore- 

 cases of this type are often called synan- 

 gia. From their appearance they have 

 been lilcened to tiny apple-dumplings. 

 Although the spore-cases are produced in abundance 

 and the spores are numerous, the plant has additional 

 means of reproduction. When it grows in soil, it may 

 send out certain slender subterranean shoots which pro- 

 duce a great many buds or bulblets by which the plant 

 multiplies rapidly. Occasionally these buds may re- 

 main dormant for a long time. The prothallia of this 

 species is unknown. 



