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A NEW SPECIES oF T OLYPELLA.—(PLATE LXXII-LXXIII.) 
TOLYPELLA MACOUNH, n. sp.—Plant 2 to 4 inches high, 
much branched, dense. Sterile leaves numerous; fertile heads 
few and very small. 
Verticils of the stem consist usually of four branches bearing 
fertile heads and eight sterile leaves; four of these sterile leaves 
are usually divided into four leaflets, of which all are simple 
terminals two-celled; or two are again divided into two or 
three terminal leaflets, and when so divided the terminals are 
usually one-celled (Fig. C); four other sterile leaves are usually 
undivided, some very long, two-celled (Fig. B); others quite 
short and three-celled; or now and then one is short, and di- 
vided into three short terminals. The sterile leaves, which are 
fully developed and bear nodes and leaflets, attain a length of 
15 to 20 mm.; the first segment shortest—4-5 mm.; the sec- 
ond, if undivided, 8-10 mm.; if divided, first part, 5-6 mm. ; 
terminals, 6-7 mm. The diameter of the first segment is 190 #. 
The pedicel bearing the fertile head (Fig. D) is about 1.25 
mm. long and 1.65 in diam. The “fertile” heads sometimes 
develop no fruit, but become quite “leafy”; in this case the 
leaves are longer and measure as follows: first division, 145 
diam., divides into four leaflets, one of these (the dorsal) extends 
longer than the others and is simply two-celled, bearing no node ; 
the three lateral leaflets again subdivide into three one-celled 
terminals. The terminals are about 120 p. in diam., avd are not 
attenuate, but end in a very short, abrupt point. See A, in plate 
LXII: 1, the pedicel of the “ fertile” verticils, one of these is drawn 
_ out, having developed sterile; 2, second segment; 3, third seg- 
ment; 4, terminal; 5, a terminal magnified 55 diam.; 6, the 
dorsal two-celled leaflet of a perfectly developed leaf, with three 
- laterals from its node (7), each divided into three one-celled ter- 
minals; C., sterile leaves variously divided. 
_ When the leaves are fertile, fruit is borne on the primary 
node of the leaf, and also on the nodes of the lateral rays; com- 
monly three sporophydia at each node ; fruit is very rarely seen 
in the fundus of the fertile verticil. Fig. D represents a fertile 
leaf with only a few fruit: 1, the first division of the leaf con- 
tinued at 1@ into the two-celled, undivided dorsal ray; 2, the 
