484 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 
THE GENUS HEMITELIA. 
In the section Eucyathea of the genus Cyathea the indusium has 
been shown to be inferior in attachment and to partially envelop 
the base of the sorus upon all sides within its cup-like walls. The 
indusium of Hemitelia is not unlike an indusium of this sort cut 
vertically in half; that is, it is deeply concave or hood-shaped when 
young, and from its point of attachment at the base of the receptacle 
bulges outward, surrounding the sporangia of at least one-half of the 
sorus upon one side. When the sporangia expand at maturity the 
indusium is borne back against the leaf surface and forced to assume 
a flattish, semicircular form. In so doing it usually splits part way 
to the base into several irregular spreading lobes. These are com- 
monly short and rounded, two to four in number, and slightly con- 
cave; but in a very few species (for example, Hemitelia muricata of 
the Lesser Antilles) the indusium becomes sharply cleft into several 
elongated, acute segments, which stand out obliquely from the leaf 
surface, mixed among the sporangia, and are not very readily 
observed, more especially since they are deciduous. Nearly all 
species of the genus, however, have indusia of the former sort; and 
this without regard to differences of leaf form. The receptacles are 
similar to those of Cyathea. 
Hemitelia is generally accepted at present as consisting of two 
sections, Euhemitelia and Cnemidaria, distinguished by differences 
in habit, leaf cutting, and venation. The first section, typified by 
Hemitelia multiflora, embraces mainly plants with upright trunks 
and large tripinnatifid fronds, similar in form to those of most species 
of Cyathea, the segments or ultimate divisions being relatively 
small. Also in free venation, scales, and minute characters other 
than those of the indusia, the half dozen or more North American 
species of Euhemitelia are precisely like those of Cyathea. The 
usual form of the indusia is shown in plate 10, figure B, representing 
H. multiflora. 
Of far greater interest is the section Cnemidaria, composed of 
plants which are rarely arborescent and whose leafy fronds are of 
very simple form. The typical and best known species of this group 
is Hemitelia horrida, which is nearly confined to the Greater Antilles. 
An unusually well-developed plant of this is shown in plate 11, 
affording an excellent idea of the broad and relatively large divisions 
of the deeply bipinnatifid, nearly bipinnate fronds. Other species 
have smaller and simply pinnate leaves, with the margins of the 
-pinne entire, undulate, crenate, or marked by regular rounded or 
angular lobes; and a few are even larger than H. horrida, with tho 
margins similarly variable in form. In some species the lobes are 
sharply acute; in others regularly rounded. There are marked dif- 
