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MARSILEACER. (WATER FERNS.) 
Perennial plants rooting in mud or wet sand, with slender creeping 
rootstocks and (in our species) quadrifoliate long-petioled leaves; frue- 
tification consisting of sporocarps borne on peduncles which rise from 
the rootstock near the base of the leaf or consolidated with it, and con- 
taining macrospores and microspores. 
1. MARSILEA L. 
Sporocarps ovoid or bean-shaped, composed of two vertical valves 
having several transverse compartments or sori in each valve, the sori 
composed of both macrosporangia and microsporangia, also provided 
with a ring which, at the opening of the valves, swells and tears the 
sori from their position. 
* Sporocarps 2 to 6 on each peduncle. 
1. M. macropoda Engelm, Plant robust: petioles 6 to 25 em. long, with large 
usually undulate leaflets which are clothed with white hairs on both sides when 
young, smoother in age: sporocarps 2 to 6 on branching peduncles, densely villose, 
6 to 8 mm. long, 5 to 6 mm. wide: sori 10 to each valve.—Rio Grande (Wright), 
Guadalupe County (Lincecum), pouds on the Seco (Reverchon), Austin (Buckley), San 
Diego (Croft). 
“ * Sporocarps solitary (rarely 2) on each peduncle. 
2. M. uncinata A. Braun, Petioles 6 em. to 2 dm. long, with nearly smooth 
entire leatlets which are 10 to 16 mm, long: sporocarps 8 mm. long, 6 mm, wide, 
borne on peduncles 1.5 to 3 cm. long, with long raphe which terminates in 2 approx- 
imate tecth, the upper longer and mostly uncinately curved: sori 13 to 14 in each 
valve.—In swamps, Dallas (Reverchon.) 
3. M. vestita Hook. & Grev. Petioles 3 to 6 em. long, with entire or slightly 
toothed leaflets: sporocarps 4 to 7mm. long, 3 to 5 mm. wide, with a short raphe 
and short usually blunt teeth, covered with pale which vary from a copious soft 
covering to short appressed beard, or rarely wanting: sori 6 to 11 to each valve. 
(Ineludes M. mucronata A. Braun, which insensibly graduates into typical forms).— 
Austin (Hall, Letterman), Dallas (Hall, Reverchon), between Cibolo and the upper 
Guadalupe (Lindhcimer), western Texas (Wright), probably widely distributed through 
the State. Var. TENUIFOLIA (Kngelm.) Underw. & Cook has petioles somewhat 
slender, 5 to 15 cm. long, with narrow villose more or less falcate leaflets with trun- 
cate and somewhat toothed apex, sporocarps5 to 8 mm. long and 4 to5mm., wide with 
divergent subequal teeth, sori9 to 11 in each valve. (M. tenuifolia Engelm.)—“ Ponds 
in the sandy post-oak woods on the Pierdenales” (Lindheimer). This interesting form 
has been only.once collected and more information is needed to determine its true 
relations, 
FILICES. (I'ERNs.) 
Plant body consisting of prostrate, ascending, or erect root-stocks, 
bearing leaves (fronds) mostly provided with petioles (stipes) and cir- 
einate in vernation; spores borne in sporangia which are reticulate, 
one-celled, and encircled by a more or less complete jointed elastic 
ring, and are collected in clusters (sori) of various forms on the under 
surface of the leaf with or without a membranous covering (indusiwm); 
