NEW MYXOPHYCEAE FROM PORTO RICO 



39 



rounded, terminal wall not thickened; sheath subgelatinous, hya- 

 line, homogeneous. 



Growing on stones in a brook in the vicinity of San Lorenzo, 

 no. 501 a, type. 



Lyngbya Kuf.tzingii minor var. nov. 



Plate 8, figure 7G 



Filaments 50-80 n long, 1.2-1.4 \\ diam., straight, erect, and 

 rigid ; cell-walls conspicuous ; sheath scarcely discernible ; other- 

 wise as the species. 



Growing on Cladophora in a pool about four kilometers north 

 of Mayagiiez, no. 1323 a, type. 



Variety minor was growing in company with what seems to 

 be typical L. Kuetzingii Schmidle. 



Lyngbya ocreata sp. nov. 



Plate 8, figure 77 



Filaments short and tortuous, not forming a definite stratum, 

 7-8.5 M diam. ; trichomes 5.6-7.2 n diam., not constricted at the 

 dissepiments'; apices very slightly attenuated; cells 1-1.4 n^long, 

 contents homogeneous, pale aeruginous ; cell walls very thin but 

 distinct ; terminal cell capitate, sheath at first hyaline and homo- 

 geneous, later becoming thicker and dense, becoming yellowish 

 and finally dark brown, in part lamellose and decidedly ocreate. 



Growing on damp earth by Playa, Fajardo, no. 710 c, type. 



The material of this species was found associated with sev- 

 eral species of Myxophyceae. The soil on which it grew is said 

 by AVille to be "brackish," but no further comment was given. 



The crooked filaments with brown ocreate sheaths remind 

 one at first of the genus Scytonema, but it has neither hetero- 

 cysts nor branching. The trichomes appear to have had several 

 periods of growth. At times they extend entirely beyond the 

 parent sheath, and are naked. iVnother region may have a hya- 

 line sheath, another farther back may be decidedly colored and 

 ocreate, the oldest part of which may be considerably thickened. 

 Apparently the species is not abundant and not widely dis- 

 tributed. 



Lyngbya scytonematoides sp. nov. 

 Plate 8, figure 78 



Filaments tortuous, not forming a definite stratum, 16-20 \x 

 diam.; trichomes 11-13 p diam., one or two apical cells tapering, 



