MARSILEACEAE 1 9 



Order 3. SALVINIALES. 



Aquatic or mud-inhabiting herbs, with horizontal or creeping stems, or float- 

 ing. Leaves various, sometimes filiform, or blades entire, lobed or 4-foliolate. 

 Spores of two kinds (microspores and macrospores), contained in sporocarps. 

 Macrospores germinating into simple prothallia which bear archegones, the 

 microspores forming still simpler prothallia bearing antherozoids. 



Plants rooting in the mud : leaves filiform or with 4-foliolate blades. Fam. 1. MARSILEACEAE. 



Plants floating : leaves with entire or 2-lobed blades. Fam. 2. SALVINIACEAE. 



FAMILY 1. MARSILEACEAE R. Br. MARSILEA FAMILY. 



Perennial herbaceous plants rooting in mud, with slender rootstocks. Leaves 

 with 4-foliolate blades, or merely filiform. Asexual propagation consisting of spor- 

 ocarps borne on peduncles which arise from the rootstock near the leaf-stalk, or 

 are consolidated with it, containing both macrospores and microspores. 



Sporocarps ovoid : leaves with 4-foliolate blades. 1. MARSILEA. 



Sporocarps globose : leaves filiform. 2. PILULARIA. 



1. MARSILEA L. 



Marsh or aquatic plants. Leaves commonly floating on the surface of shallow water ; 

 blades slender-petioled, 4-foliolate. Peduncles shorter than the petioles, arising from 

 their bases or more or less adnate to them. Sporocarps ovoid or bean-shaped, composed of 

 two vertical valves with several transverse compartments (sori) in each valve. 



Sporocarps 2-6 on each peduncle : leaves pubescent on both sides. 1. M. macropoda. 

 Sporocarps solitary or rarely 2 on each peduncle. 



Leaflets 4-16 min. broad, obovate or nearly obcordate. 



Sporocarps 3-5 x 4-7 mm.; raphe short, with acute teeth. 2. M. vestita. 



Sporocarps 6X8 mm.; raphe long, with long hooked teeth. 3. M. uncinata. 



Leaflets 2-4 mm. wide, more or less falcate. 4. M. tenutfolia. 



1. Marsilea macropoda Engelm. Plant robust, 10-25 cm. tall. Leaflets 2-5 cm. 

 long, 2 cm. wide, or narrower, usually undulate, pubescent with white hairs on both sides, 

 especially so when young: sporocarps 2-6 on erect branching peduncles, densely villous, 

 6-8 mm. long, 5-6 mm. thick : raphe short, the lower tooth obtuse, the upper prominent 

 or wanting : sori 10 in each valve. 



In muddy places, Texas and New Mexico. 



2. Marsilea vestita Hook. & Grev. Rootstock slender. Petioles 5-13 cm. high : 

 leaflets entire or toothed : sporocarps 4-8 mm. long, 4-6 mm. wide, with a short raphe, 

 a short and blunt lower tooth and an acute and sometimes curved upper one, densely cov- 

 ered with soft spreading narrow hair-like scales, or in certain forms these are short and 

 appressed or almost wanting : sori 6-11 in each valve. 



In wet sand or in shallow ditches, Kansas to British Columbia, Mexico, Texas and Florida. 



3. Marsilea uncinata A. Br. Plant 6-20 cm. tall. Leaflets nearly glabrous, entire, 

 10-16 mm. wide, 8 mm. long : peduncles 15-30 cm. long, 2-4 times the length of the 

 sporocarps : raphe long, terminating in 2 approximate teeth, the upper longer and mostly 

 uncinately curved : sori 13-14 in each valve. 



In swamps, Louisiana and Texas. 



4. Marsilea tenuifolia Engelm. Plant slender, 5-15 cm. high. Leaflets 2-4 mm. 

 wide, more or less falcate, often slightly truncate and unequally toothed at the apex, ap- 

 pressed-pubescent : sporocarps solitary, 5-8 mm. long, 4-5 mm. wide, the teeth nearly 

 equal, divergent : sori 9-12 in each valve. 



On borders of ponds, Pierdenales, Texas. 



2. PILULARIA L. 



Marsh plants with slender creeping rootstocks and few filiform leaves. Sporocarps 

 globose, longitudinally 2-4-celled, dehiscing from the apex : cavities with parietal cushions 

 bearing microsporanges above and numerous macrosporanges below. Macrospores solitary. 



1. Pilularia Americana A. Br. Leaves filiform, about 2.5 cm. long. Sporocarps 

 2 mm. in diameter, attached by the side to a short descending peduncle, 3-4-celled : micro- 

 spores 13-17, not constricted at the middle. 



In shallow pools, Arkansas and California. 



