ROBINSON: PTERIDOPHYTA OF THE HAWAIIAN ISLANDS 237 
forms; sporangia developed from a single epidermal cell, mainly 
upon the under surface of the leaf, in clusters (sori) upon the veins, 
or within marginal indusia, or less commonly, scattered over the 
entire lower surface or upon non-foliose sporophyls. Indusia 
Various or wanting. Prothallia chlorophyllous, thalloid. 
Sporangia borne in a distichous spike; sterile leaves slen- 
der, grasslike. 
Sporangia associated in indusiate or non-indusiate sori or 
scattered over the lower surface of the leaf 
Leaves pseudo-dichotomous, usually with a bud be- 
I. SCHIZAEACEAE. 
tween the paired divisions, giving the appearance of 
indefinite growth; sori non-indusiate, small, circu- 
lar. 2. GLEICHENIACEAE. 
Leaves simple, pinnately divided, or ternately divided. 
ri valvate or tubular. 
Sori valvate, the outer valve formed by a 
coriaceous outgrowth from the margin of 
the leaf, dorsal upon the veins; plants 
boreous. 
Sori valvate or tubular, not coriaceous; ter- 
minal upon the veins; plants delicate, 
mostly epiphytic. 
Sori not valvate or tubular; indusium various or 
absent. 
3. CYATHEACEAE, 
4. HYMENOPHYLLACEAE. 
5. POLYPODIACEAE. 
1, SCHIZAEACEAE 
Plants of diverse form and habit, including xerophilous forms 
with simple leaves and climbing plants with lobed or divided 
leaves, Sporangia borne singly or in rows on more or less special- 
zed terminal segments, or upon the very slender non-foliose 
Pinnae, indusiate or non-indusiate; annulus subapical, distally 
Contracted; dehiscence longitudinal. Prothallia foliose or fila- 
mentous and branched. 
SCHIZAEA J. E. Smith, Mém. Acad. Turin §: 419. 1793 
Rootstock short, upright, covered with dark-brown scales; 
leaves linear » gtasslike; sporophyl consisting of a long slender 
— and a digitate fertile portion folded upon the midrib; spo- 
Fangia borne in two rows upon each division. 
Type species: Schizaea dichotoma J. E. Smith. 
