28o 



THE GAMETOPHYTE, AND SEXUAL ORGANS [ch. 



A similarly filamentous and profusely branched gametophyte has been 

 observed in a number of species of Trichonanes (Fig. 270). It is composed 

 of oblong chlorophyll-containing cells, and the branches arise from the distal 

 end of each, while dark brown 

 rhizoids attach it to the substratum. 

 Not uncommonly fungal hyphae 

 are associated with it externally, 

 but no distinctive organs like the 

 spherical cells of ScJiizaea have 

 been noted. In some species the 

 filaments may widen out into broad 

 flattened expanses one layerof cells 

 thick, as in T. alatum (Fig. 271, C). 

 The relation of these to the fila- 

 mentous part may be very irregu- 

 lar, as is also their outline. The 

 way they originate is by repeated 

 transverse segmentations followed 

 by longitudinal divisions (Fig. 271, 

 A, B). But they never seem to 

 take the cordate form. 



Many years ago Cramer noted 

 on an unknown filamentous game- 

 tophyte the formation of spindle- 

 shaped gemmae, which were clearly 

 organs of vegetative propagation. 

 Similar gemmae have since been 

 found on prothalli of various species 

 of Trichojnanes{ T. alatum, vetiosiim, 

 a.r\d pyxidiferum,Qic.). They are borne distally, sometimes upon simple fila- 

 ments but more frequently at the ends of the flattened expanses (Fig. 271, 

 C, D, E). Distal cells grow out forming sterigmata, and their ends become 

 distended transversely, taking a spindle-shape, and undergoing segmenta- 

 tions. These bodies consisting of about six cells are stored with nutriment, 

 and are easily detached from the brittle neck of the flask-shaped sterigmata, 

 as gemmae. Their germination reproduces the filamentous prothallus 

 (Fig. 271, D,E,F). 



The sexual organs of TricJwnianes are borne very much as in Schizaea, 

 the antheridia corresponding in position to dwarf branches (Fig. 272, a — d). 

 The archegoniophores are, however, more complicated, and of larger size, 

 bearing a number of archegonia, their ventral region being immersed in a 

 mass of parench)'ma (Fig. 272, c,f,g). 



Fig. 270. Trkhoniajies rigiduni,^\N. Habit of a pro- 

 thallus, of which only a small portion is represented, 

 with archegoniophores {A), on one of which (the 

 lower) an embryo-plant is seated. ( x about 50.) 

 (After von Goebel, from Engler and Prantl.) 



