Lemaneaceae of the United States . 183 
in Figs. 53, 54, 55, 56, which are varieties of this species. By- 
referring to the explanation of the plates and the description 
of this species in the systematic part, the varietal names and 
habitats of these forms can be ascertained, 
In the form represented by Fig. 55 the papillae are very 
prominent and the portion of the sexual shoot between them 
is nearly or quite cylindrical. There are no £ hard and fast ’ 
lines between these varietal forms, so one will be likely to find 
great variation in the number and form of the papillae and the 
shape of the portion of the sexual shoot between them, even 
in material from the same locality, though most of the forms 
can be grouped around one or another of these. 
The summits of these papillae will appear, even with a small 
hand-glass, of a different structure from the other portions of 
the surface of the plant. The elements are very much finer 
in structure and often of a slightly different color. So where 
the papillae are not prominent above the surface of the plant, 
as in some forms, the spots which correspond to them in 
structure, and as we shall later see in function also, can easily 
be seen. The fine elements making up the surface structure 
of these spots are the male organs, or antheridia. Sometimes 
these papillae become so numerous or large that they may be 
confluent in a ring around the enlargement, as is shown in Fig. 
53, but by far the greater number of them will be separate 
and distinct, so that by examining the whole length of the 
plant it will be easy to determine if the specimens belong to 
this natural group. The members of this group belong to 
Sirodot’s 1 genus Sacheria . 
If we now make a similar examination of a specimen of the 
other natural group the external differences will be manifested. 
The enlargements are not papillate, but are plane, rarely 
angular. Figs. 47-5 1 and 57 represent portions of the sexual 
shoot of several different species. The antheridia here, 
instead of being in definite patches, are almost always con- 
fluent into a more or less regular band around the middle of 
1 Ann. d. Sci. Nat., etc., loc. cit. 
