68 



MEMOIKS OF THE XEW YORK BOTAXICAL GARDEN 



Growing on the wall of a house in ^Maricao, »o. 1049, type. 



Calothrix Brauxii mollis var. nov. 



Filaments growing in small tufts 80-110 m long, decidedly 

 bulbous at the base, 8-10.8 \x diam. at the base; triehome tapering 

 gradually from the base, terminating in a slender hair as long 

 as or longer than the main body, bright aeruginous, 5-6 \x diam. 

 at the base; hair 1.4 |j diam.; sheath hyaline, oereate. 



Gro^^-ing on earth among other ^Myxophyceae. Maricao, no. 

 1037 h, tji)e. 



Calothrix linearis sp. nov. 

 Plate 13, figure 21 



Filaments attached at the base, erect and straight for the most 

 part, 350-500 M (up to 1000 n) long, cylindrical except a short 

 distance at the iDase and at the apex; trichomes linear, cylin- 

 drical throughout except a few cells at the base and at the apex, 

 the former being slightly larger and the latter tapering into a 

 short hair, 5-7 \x diam. ; cells c[uadrate, one-half as long as the 

 diameter, in part constricted at the dissepiments ; heteroeysts 

 basal, single, or at times more than one, mostly hemispherical: 

 branching usually near the u]3per end ; hormogonia fairly abun- 

 dant ; sheath subgelatinous, hyaline, homogeneous, 2-2.5 \i thick. 



Growing on a water pump in Maricao, no. 1276 a, type ; on a 

 wall near a bridge in Caguas, no. 461 c. 



Calothrix linearis is a very distinct species. Dr. AVille had 

 suggested in his notes that the material should be made the type 

 of a new genus, based on the non-attenuated character of the 

 triehome. The genus would thus occupy a position between 

 Calothrix and Microchaete, branching as in the former genus 

 and non-attenuated as in the latter genus. Many of the trichomes 

 are actually slightly larger at the apex than they are further 

 back, as large even as the few largest cells at the base, and in a 

 few instances trichomes with a heterocyst on both ends were ob- 

 served. Careful search revealed the fact that some of the young 

 trichomes have short tapering apices with terminal hairs. On 

 this account it seems best not to establish a new genus for its 

 reception as probably all of the trichomes in their earliest stages 

 of development produce short ephemeral hairs. After these 

 drop off. meristematic regions are established in many instances 



