28 



260 diam.; ultimate segments 40 to 45 diam.; mucro 20 to 25 diam. by 

 40 to 105 long. 



This species differs from N. tennis sima by its mucus envelope, by the 

 larger black nucleus, sporangia in each division of the leaf, and by its 

 long loose leaves ; from N. batrachosperma, by its size, its long loose 

 leaves in many rays thrice divided, and by its larger antheridia ; from JV. 

 gracilis by its mucus, by the larger black sporangium with more promi- 

 nent striae and by the segments of the third division of the leaves not 

 being three-celled; from N. leptosoma, genuma, by the loose conform- 

 able verticils of leaves (thrice divided) and by the inferior cell of the 

 ultimate segments not being gradually attenuate ; it is, moreover, dis- 

 tinct from all the above by the structure of the colored membrane of 

 the nuclei of the sporangia. 



In the plate the " natural size " figure was drawn from a fresh specimen, with the 

 younger, fertile verticils enveloped in mucus. 



NITELLA ASAGRAEANA Schaffner, in Herb. Farlow. 



Plant 15 to 20 centimeters long, branched; lower verticils of five or 

 six spreading, sterile leaves; upper verticils becoming rather suddenly 

 condensed into close, interrupted, spike-like masses of fertile, con- 

 tracted leaves, enveloped in mucus. The lower spreading leaves are 

 about 20 to 30 mm. long, divided first into four short leaflets (2 to 5 

 mm. long), each of which is subdivided into three short terminals about 

 half a mm. long, two-celled, terminating in sharp mucronate points. 

 Diameters of sterile leaves: First segment 340, first division 265, ter- 

 minals 125; mucro (which seems to be very evanescent, dropping 

 easily and rarely found in older leaves), 48 at base, 115 to 120 long, 

 very sharp. The upper sterile leaves are often partly fertile. The con- 

 tracted fertile leaves are five (rarely six) in a verticil, once or twice 

 divided ; the terminal segments, two or three in number, terminate in 

 a sharp mucro. The fruit is borne on both nodes of the leaf; isolated ; 

 the oospore 272 to 290 long, 175 to 190 (or even 230) broad, with five 

 or six sharp and prominent spiral ridges; the surface grumous. 



This plant was collected by Dr. J. G. Schaffner in 1876 in stagnant 

 pools about Morales, near San Louis Potosi, Mexico, and appears in 

 Herb. Farlow as No. 6 of his Flora Mexicana (exsiccatae?). The name 

 is given as spelled on the original label. This original specimen is in a 

 tangled condition, and could not be satisfactorily studied without injur- 

 ing the plant (which is quite undesirable) ; new collections may possibly 

 change somewhat the general description in minor particulars. The 

 figures on the plate require no explanation further than to explain that a 

 mass of mucus envelops the upp^r suddenly abbreviated fertile verticils. 



