KEY TO THE GENERA OF HAWAIIAN FERNS AND FERN ALLIES 
Irwin E. Lane 
\7 
s to the species may be found in Robinson: Bulletin of the Torrey 
Tt 1 /■» 
aa.ti.oa 
O 1 
oz 
UIUD 39: 227-248; 567-601; ibidem 40: 193-228; ibidem 41: 51-59. Descrip- 
most species may be found in Hillebrand; Flora of the Hawaiian Islands. 
Bot 
tions 
Since 
longer considered to belong, a list of synonyms under which they may be found 
the older works is appended. 
many of the species are keyed and described in genera in which they are no 
1 
XU 
This key presupposes a knowledge of the ferns such as would be gained from a 
study of a general botany text. The following special definitions of terms are to 
be noted: Vernation is the position of the leaves in the bud, circinate if the 
the 
leaf 
unrolls 
JLLi 
cr 
o 
rowth. Valvate is opening like a door or lid. Indusium i, 
membrane which surrounds or covers the sorus or cluster of sporangia. Receptacle 
is a stem-like projection of tissue, surrounded by the tubular indusium in the 
Hymenophyilaceae, upon which the sporangia are borne. Articulate means jointed, or 
falling with a clean break. Alate means winged, with a thin strip of blade on one 
or both sides of a petiole or rachis. An areola is the mesh or space between the 
veins in a reticulate veination. 
1 - Spores produced in capsules on rhizomes, aquatic plants with fronds 
simple in plan (Salviniales) ..... 2 
1 - Spores borne upon some aerial part of the plant, if aquatic then 
fronds deeply dlsected ..... 3 
2 - Plants floating, tiny; leaves with entire or 2-lobed blades, 
folded in vernation (Salviniaceae) ... 
Azolia 
2 - Plants rooted in the mud; leaves 2-4 foliate, circinate 
in vernation (Marsiliaceae) ... 
Marsilia 
3 
Sporangia borne in the axils of 
distant or form compact cones 
scale-like leaves which are either 
(Lycopodiales) .. 
4 
3 - Sporangia not borne in the axils of scale-like leaves ... 6 
4 - Sterile leaves in four rows, of two distinct sizes on each branch, 
Heterosporous; sporangia of two kinds (Selaginellaceae)..... Selaginella 
4 - Sterile leaves spiral around the stem, of similar size or none, 
homosporous; sporangia all of one kind ....... 5 
5 - Sp orangia i-ceiled; stems with small or scale-like leaves,... Lycopodium 
5 - Sporangia 2- or 3-celled; stems apparently without leaves 
(Psilotaceae)..... Psilotum 
6 - Vernation erect or inclined; sporangia sessile and borne on a 
non-leaf-like branched or unbranched stalk, which may arise 
from a leaf (Ophioglossaceae) ....... 7 
6 - Vernation circinate; sporangia usually on stalks, or, if sessile, 
then appearing on the surfaces of leaves.... ................. 8 
r 
