66 



MEMOIRS OF THE 2^EW YORK BOTANICAL GARDEN 



Growing on stones in a stream near Maricao, no. 1128, type. 



The plants mostly appear to be young in this species of 

 Leptochaete as represented by the specimens in the collection, 

 but seem unmistakably to be a distinct species. 



Calothrix conica sp. nov. 



Plate 13, figure 18 



Filaments only very slightly swollen at the base, branching 

 very sparse, up to 125 \i long, but mostly 45-65 \x long, 6.8-7.5 \i 

 diam. at the base, straight or in part more or less curved, ahnost 

 equidiametric throughout the entire length ; trichomes 4.8-5.6 n 

 diam., 1-3 cells slightly larger at the base, and 1-3 cells attenu- 

 ated at the apices ; ajjical cell conical ; no indication of any hair 

 cells; cells cylindrical below, decidedly dolioform above, quad- 

 rate below to slightly shorter above, aeruginous, homogeneous ; 

 heterocysts sj^herical to subspherical, single, basal, conspicuous; 

 sheath hyaline, thin and close-fitting, ephemeral; hormogonia 

 short. 



Growing on trees in a ravine near Coamo Springs, no. 1895, 

 type. 



Calothrix conica is apparently related to C. tenella of this 

 paper and to C. epiphytica W. & G. S. West. It is to be dis- 

 tinguished by the conical apices, almost cylindrical trichomes, 

 dolioform, almost moniliform cells in the upper part of the 

 trichomes and by the delicate hyaline ephemeral sheath. There 

 is no indication of hairs. They may apj^ear, however, in the 

 early stage of the development of trichomes. 



Calothrix simplex sp. nov. 



Plate 13, figure 19 



Filaments 200-250 \i long, attached at the base, erect and 

 straight or a few curved close to the base and erect, forming a 

 continuous stratum with other ]\[yxophyceae, tapering gradually 

 and uniformly from tlie basal cell to the long apical hair, or in 

 some of the oldest filaments, 2-4 basal cells somewhat larger, 

 making a slight bulbous base, up to 18 \i diam. at the base 2-2.5 p 

 at the apex ; trichomes 10-14 yi diam. at the base, aeruginous, not 

 constricted at the dissepiments ; cells one-third to one-fourth the 

 diameter long, homogeneous ; heterocysts single, all basal, hemi- 

 spherical to elongated, hyaline ; sheath thin, firm, smooth, homo- 



