30 PSILOTACEAE 



phytic, it usually grows in humus on the hammock floor. 

 It may be expected anywhere in a hammock, but often in 

 open places or areas of partial shade it forms impenetrable 

 tangles with such a copious growth of leaves that the 

 mass will support men walking over it several feet 

 above the ground. This plant must be granted the dis- 

 tinction of having the longest leaves of any of our ferns. 

 Leaves approximately eighteen feet long are not uncom- 

 mon, while the maximum length is twenty-seven feet 

 three inches. The long leaves are often vine-like. They 

 clamber over shrubs and up tree trunks and hang over 

 the limbs of the trees. It was discovered in Florida in 

 1887, and is now known as far north as the Lake Okee- 

 chobee region. The geographic range of the species in- 

 cludes both continental and insular tropical America. 



Order 2. LYCOPODIALES 



Terrestrial or epiphytic plants. Sporangia borne 

 in the axils of scale-like leaves, 1-celled or 2- or 3- 

 celled. Spores all of one sort and size or of two 

 kinds and sizes. Embraces the following family and 

 Lycopodiaceae. 



FAMILY 1. PSILOTACEAE 



PSILOTUM FAMILY 



Perennial slender terrestrial or epiphytic plants, 

 apparently leafless on account of the greatly reduced 

 and therefore inconspicuous leaves. Sporangia ses- 

 sile in the axils of the scale-like bracts on the branches, 

 2- or 3-celled, 2- or 3-lobed, opening by valves at the 

 apex. Spores uniform. Comprises two genera, 

 Tmesipteris of Australasia and the following. 



