HoLLOWAY. — Studies in the Neiv Zealand Species of Lycopodium. 197 



of the tree-fern stem-surface that the prothalli and plantlets of both L. Bil- 

 lardieri var. gracile and of Tmesipteris occur. As the tree-fern grows in 

 height the covering of aerial rootlets spreads up the stem, and so plantlets 

 of increasing age have to be carefully dissected out from the mass of the 

 brittle rootlets. The prothalli of this species of Lycopodium are often to 

 be found adhering closely to the hard black surfaces of the stipites, and 

 are there readily found by tearing away the humus and the debris of old 

 tomentum which collects between the bases of the stipites. Their rather 

 delicate, attenuated form is probably the result of this particular position 

 of growth. 



Fig. 6. — L- varium. Prothallus in general view, showing central body and 



branches, and a young plant, x 10. 

 Fig. 7. — L. varium. Prothallus in general view, showing basal end, and young 



embryo in the generative region. X 10. 

 Fig. 8. — L. varium. A branched " resting " process in general view. X 10. 



The prothalli of L. Billardieri, on the other hand, occur for the most 

 part in masses of humus on elevated positions in the forks of the forest 

 trees and of their main branches. The central prothallial^body is generally 

 more bulky than that of L. Billiardieri var. gracile, but otherwise the 

 prothallus is identical both in appearance and in structure. With regard 

 to the tropical forms studied by him, Treub states that the prothalli of 

 L. Hippuris are much larger and thicker than those of L. Phlegmaria, while 

 those of L. nummidarifolium are exceedingly thin. These epiphytic pro- 

 thalli have very much the appearance of a mass of root-ends, but a little 



