74 Veit Brecher Wittrock. 



EXPLANATION OF THE PLATES. 



The following letters apply to all the figures. 



ac, accessorial branch. 



h, b^, b'^, b^, b'*, normal branches of different degrees. 



bs, bs-, bs'^, subsporal branches, i. e. branches brought forth by subsporal cells. 



bsp, branch developed from the side of a spore which remains attached to the mother 

 specimen. 



c, inclosed vegetative cell. 



ct, terminal vegetative cell. 



h, helicoid. 



p, prolific cell. 



rh, rhizoïd part of the thallus. 



s, inclosed cask-shaped spore. 



s, the elder one of a pair of twin spores. 



s', the younger one of a pair of twin spores. 



fii, the oldest one in a group of triple spores. 



s'^, the middle one in a group of triple spores. 



s', the youngest one in a group of triple spores. 



sb, basal spore. 



sc, inclosed cylindric spore. 



sf, branch in which the act of spore-formation is taking place. 



sg, the oldest part of the specimen, i. e. the part which has belonged to its mother 

 spore. 



sgb, basal spore formed by the lowest cell of the cauloïd, within the same cell- 

 membrane as the mother spore of the specimen. 



.li, spore of an irregular shape. 



sp, s^j, spore which supports a branch. 



sr, a spore furnished with a rudimentary branch process. 



ss, sessile spore. 



st, a terminal cask-shaped spore with a tapering top. 



stc, terminal subconical spore. 



w, ÎV, iv", transversal cellwall. 



PLATE I. 



The figures are magnified 25 times, with the exception of fig. 8, 

 which is magnified 20 times, and fig. 10, 50 times. 



Figs 1 to 3. Pithopliora sumatrana (v. Mart.) nob. 

 Fig. 1. A piece of the principal filament of the cauloïd with two short branches; 

 the lower branch formed by only one sessile terminal spore, st. 



