284 TUFTS COLLEGE STUDIES, Voi,. II, No. 3 



such quantity as to give a whitish appearance to algae normally 

 brown. The circumstances favorable to its development favor 

 also other small epiphytes, and it is usually accompanied by 

 Calothrix parasitica, Streblonema species, etc. It is usually 

 found in brown algae, Leathesia difformis, Castagnca virescens, 

 Mesogloia divaricata, Ralfsia Borneti, etc. ; sometimes in old 

 plants of Dictyosiphon and Scytosiphon, where the normally com- 

 pact cortical layer has become loose ; occasionally in red algae 

 such as Nemalion rmdtifidum and N. Andersonii. 



9. PSEUDENDOCLONIUM Wille, IQOI, p. 29 



Frond of much and irregularly branched filaments, packed to- 

 gether in an irregular layer, with short, erect branches, and 

 with very short rhizoids ; cells of irregularly rounded shape ; 

 chromatophore a small parietal disk with one pyrenoid. Asexual 

 reproduction by akinetes, and by 4-ciliate zoospores without 

 stigma. 



Only one species. 



P. SUBMARINUM Wille, 1901, p. 29, PL III, figs. 101-134; 

 P. B.-A., No. 1124. Cells 6-7 & diam., forming a pseudopar- 

 enchymatous layer on the surface of and penetrating more or 

 less into the substance of woodwork, near high water mark ; 

 akinetes of two types, one with wall little thickened, germinat- 

 ing at once ; the other with thick walls and remaining in the 

 resting state for some time ; zoosporangia slightly larger than 

 the vegetative cells, producing each 4-8 4-ciliate zoospores, 

 about 4 i*. diam., escaping by a short neck; germinating im- 

 mediately. Fig. 87. Me., Mass., R. I. Europe. 



This species forms a fine green granular coating on shaded 

 woodwork near high water mark, and in appearance much re- 

 sembles the common Pleurococcus vtilgaris ; but is distinctly fila- 

 mentous, and appears to be a reduced form belonging to the 

 Chaetophoraceae . 



10. ENDOCLONIUM Szymanski, 1878, p. 18. 



Frond endo- or epiphytic, forming larger or smaller disks, 

 filaments erect at the margin, and here and there in the disk, 

 forming erect, branching tufts. Asexual reproduction by akin- 

 etes, and by small biciliate and larger 4-ciliate zoospores, with 

 red stigma, formed one to several in a cell ; sexual reproduction 

 by small biciliate gametes. 



A genus of minute plants inhabiting the leaves of various 

 aquatic plants, probably closely allied to Stigfoclonhim. We 



