MARSILEACEAE. 
2. Marsilea vestita Hook. & Grey. 
Hairy Marsilea. (Fig. 74.) 
ssh Lag vestita Hook. & Grev. Ic. Fil. p/. 759. 
1831. 
Marsilea mucronata A. Br. Amer. Journ, Sci. 
(II.) 3:55. 1847. 
Rootstock slender, creeping. Petioles 
slender, 2’-5’ high; leaflets similar to those 
of the preceding species, entire or toothed ; 
sporocarps 2’/-4’’ long, 2’/-3’’ wide, with a 
short raphe, a short and blunt lower tooth 
and an acute and sometimes curved upper 
one, densely covered with soft spreading 
narrow hair-like scales or (in the forms 
known as J/. mucronata) these short and 
appressed or almost wanting; sori 6-11 in 
each valve. 
In wet sand or in shallow ditches, Florida 
to Kansas, Arizona and Mexico, north to British 
Columbia. 
Family 7. SALVINIACEAE Reichenb. Consp. 30. 1828. 
SALVINIA FAMILY. 
Small floating plants with a more or less elongated and sometimes branching 
axis bearing apparently 2-ranked leaves. Sporocarps soft, thin-walled, borne 
2 or more on acommon stalk, 1-celled, with a central often branched receptacle, 
which bears macrosporanges containing a single macrospore or microsporanges 
containing numerous microspores. ‘The macrospores germinate into prothallia 
which bear archegones, the microspores into prothallia which bear antherids. 
‘The family consists of two genera. 
Leaves 6''-9'’ long, 2-ranked, on mostly simple stems. 1. Salvinia, 
Leaves minute, closely imbricated on pinnately branching stems. 2. Azolla. 
1. SALVINIA Adans. Fam. Pl. 2:15. 1763. 
Floating annual plants with slender stems bearing rather broad 2-ranked leaves. 
Sporocarps globose, depressed, 9-14-sulcate, membranous, arranged in clusters, 1 or 2 of 
each cluster containing Io or more sessile macrosporanges, each containing few macrospores, 
the others containing numerous smaller globose petlicelled microsporanges with very 
numerous microspores. Leaves rather dark green, finely papillose on the upper surface. 
[Name in honor of Antonio Maria Salvini, 1633-1729, Italian scientist. ] 
About 13 species of wide distribution. Only the following occurs in North America. 
1. Salvinia natans (L.) Hoffm. Salvinia. : 
(Fig. 75.) 
Marsilea natans V,. Sp. Pl. 1099. 1753. 
Salvinia natans Hoffm. Deutsch, Fl. 2:1. 1795. 
Leaves oblong, rather thick, obtuse or emargin- 
ate at the apex, rounded or cordate at the base, 
entire, spreading, 6/-12’ long, pinnately veined, 
bright green and papillose above, the lower surface 
densely matted with brown pellucid hairs; sporo- 
carps 4-8 in a cluster, the upper ones containing 
about 10 macrosporanges, each containing a few 
macrospores, the remainder containing numerous 
microsporanges each with numerous microspores ; 
macrospores marked with 3 obtuse lobes which 
meet at the apex. 
Bois Brulé Bottoms, Perry Co., Missouri and near 
Minneapolis, Minn. Introduced into ponds on Staten 
Island, N. Y. Reported by Pursh in 4814 from central 
New York, but his exact station is unknown. Widely 
distributed in Europe and Asia. 
