438 



The plant (Fig. 413) forms small, low tufts upon the host plant, 

 Dictyota indica, from which the longer main filaments protrude. 



The base (Fig. 414 a) of the 

 plant consists of freely ramified 

 filaments creeping upon the surface 

 of the host and fixed to it by means 

 of quite short, small rhizoids (Fig. 

 414 b). The filaments have apical 

 growth and the branches are given 

 off from the distal end of the cells 

 at both sides, now alternating, now 

 opposite or sometimes, too, unila- 

 teral. The filaments are mutually 

 free. The cells in the basal filaments 

 contain well developed chromato- 

 phores; the cells are about 10 (J broad 

 and 20 jii long. 



From the cells of this base the 

 different erect organs are given off, 

 namely: short branchlets, hairs, long 

 main filaments and more rarely 

 plurilocular sporangia (comp. Fig. 

 413 a and 414 a, b). The short 

 branchlets are commonly unbranch- 

 ed, nearly cylindrical with obtuse 

 apex, composed of about six cells 

 reaching a height of about 150 u. 

 and a breadth of 12 //, more rarely 

 ramified. 



The hairs have one or two basal 

 cells of which the lowermost is the 

 longest ; above these cells the growth 

 zone follows. Upwards in the hairs 

 the cells rapidly increase in length, 

 being very long in the upper end. 

 The hairs are about 12 |u thick. 

 The few plurilocular sporangia found growing out from the 

 basal filaments had, at their base, a single or a few sterile cells, 

 about 8 9 u. broad. The sporangia are elongated-spindle-shaped, 

 about 80 u long and 20 u broad. 



Fig. 413. Myriotrichia occidentalis 

 nov. spec, a part of a, plant with 

 sporangia (someones emptied). 

 b, apex of a filament with ter- 

 minal hair. (a. about 150:1; 

 b, about 250:1.) 



