THE PSILOTACE^. 



NE of the most curious of all the fern 

 allies, and one of the rarest in our flora, 

 is that relative of the lycopodiums 

 which botanists call Psilotuin triquctruin. 

 This, in fact, is often considered as 

 one of the Lycopodiaceze, and in many 

 books will be found included as one of the four genera 

 supposed to belong to that family ; but the typical 

 Psilotum form is so different from that of Lycopodiuui 

 that in the opinion of modern botanists we are war- 

 ranted in placing the species in a separate family which 

 has been named the Psilotacere. In this family, as now 

 recognised, there is the single genus Psilotuin, and in 

 this genus less than half a dozen species. Baker's " Fern 

 Allies " names but two species and several varieties. 

 Others are inclined to give some of the most pronounced 

 of these varieties specific rank, but in any event the 

 genus will always remain with very few species. The 

 family being so small, a description of our single species 

 will sufifice for an account of the whole family. 



Like many of its relatives among tropical lycopo- 

 diums, our species (PsilotJim triquctruin') is epipl"i3?tic and 

 usually grows on the trunks of trees, though it is occa- 

 sionally found upon the earth, on fallen logs, or the like. 

 The mature plant has no true roots, from which it is con- 

 jectured that it is a saprophyte, like the mushrooms. 



