PrAte Ve AC 
Nie LAVALLE XTCIS. Ae: 
Var. nidifica Wallm. (1353). 
NV. flextlis, var. subcapitata A. Br. (Br. Rahen. u. Stizenb. Char. exsic. No. 23. 
Ch. nidifica Hutm., Sk. Fl. ed. 5. (4. glomerulifera A. Br., in Silliman’s Journ. 
1843, reported from New Hampshire, seems rather a variety of iV. acuminata A, Br.) 
This variety differs from the normal form in the suddenly abbreviated and crowded 
verticills of the upper leaves; due apparently to a great expenditure of energy in 
producing fruit. Frequently we find all the leaflets converted into sporangia and_ the 
leaf or stem correspondingly shortened. The general habit of the plant is, however 
that of forma brachyphylla, for even the sterile leaves are short, though in many of our 
specimens the internodes are quite long 
The variety seems constant for it recurs year after year in the same locality growing (in 
Litchfield, Ct.) along with the normal and long-leaved form. 
In the tendency of this species to form dense heads of fruit at the expense of the 
growth of stem and leaf, we find a great similarity to iV. capitafa and to capitate forms 
of WV. opaca. Indeed, were it not for the dicecious character of the latter species, it 
would be difficult to distinguish it from /exizs. The mature spore of JV. ofaca has not 
the prominent angles of that of JV. flexz/cs; both species are very variable as to size, 
and sterile plants caznzot be determined with any certainty. 
This variety offers good advantages for the study of the fertilization of the ovule by the 
spermatozoid. In the Nitellea generally, the spermatozoid enters the sporangium 
through fissures which open between the cells at its neck ; the cells at the neck become 
small and do not retain the thickness of the lower portion of the investing cells 
of which they are a continuation ; as the space under the coronula enlarges, openings 
form between these cells, at the neck of the sporangium, and the spermatozoid, on 
the rupture of the eanthertdiam (which takes place when the sporangium is yet quite young) 
passes through these fissures into the space beneath the coronula and thence downward to 
the ovule. In this species and ina few others, nearly related, these fissures do not form, but 
the spermatozoid enters at the top between the cells of the coronula, an opening being 
formed by the rising up and separation of the cells, caused by the enlargement of the 
space under the coronula. (A. Braun). 
