Vittariaceae; Marsileaceae; Salviniaceae 



107 



4. Vittaria forrestiana Ching. Oba-shishi-ran. Rhi- 

 zomes creeping, scaly, the scales rusty-brown, very thin, lan- 

 ceolate, about 1 cm. long, long-acuminate, ascending; fronds 

 crowded, softly herbaceous, lanceolate, 15-25(-40) cm. long, 

 ].5(-3) cm. wide, gradually attenuate at both ends, short- 



stipitate, entire, hyaline on margin, flat; costa prominent on 

 both surfaces, the veins somewhat evident, very oblique, 



slender; sori superficial, intramarginal. Kyushu (Yaku- 



shima, according to M. Tagawa). China and Indochina. 



Fam. 22. MARSILEACEAE Denji-so Ka Marsilea Family 



Mostly aquatic, growing in mud, rarely floating or aerial; rhizomes creeping, solenostelic, hairy; leaves simple, linear, or with 

 one or two pairs of leaflets at the end of a long petiole; veins freely forked and anastomosing at the apices; megasporangia and 



microsporangia enclosed in different sporocarps; sporocarps bony, borne on stipes or basal. Three genera with about 70 



species. 



1. MARSILEA L. Denji-so Zoku 



Leaves 4-foliolate; sori numerous on a gelatinous receptacle attached to the wall of the sporocarp.- 

 politan, especially abundant in Australia and S. Africa. 



1. Marsilea quadrifolia L. Lemna quadrijoUa (L.) 

 Desr.; Zalusianskya quadfijolia (L.) O. Kuntze; Pteris qtiad- 



rijoliata L.; M. quadrijoUata (L.) L. Denji-so. Aquatic 



or hygrophytic summergreen perennial with brownish yellow 

 appressed to ascending soft hairs \^'hile very young; rhizomes 

 slender, long-creeping, 1.5-2 mm. in diameter; leaves radical, 

 few, the petioles 5-15 cm. long; leaflets or pinnules 4, thinly 

 chartaceous to membranous, sessile, deltoid-flabellate, 1-2 cm. 

 long and as wide, broadly rounded at ape.x, broadly cuneate 



-Nearly 70 species, cosmo- 



at base, entire, glabrous on upper surface; veins slender, nearly 

 parallel, forked, somewhat anastomosing; pedicels short, 2-3- 

 nate, connate, adnate to the base of stipe, erect; sporocarps soli- 

 tary on a pedicel, ellipsoidal, 4-5 mm. long, densely pubescent 



at first, becoming glabrous, the basal toodi minute. Sept.- 



Oct. Paddy fields and ponds; Hokkaido, Honshu, Shikoku, 

 Kyushu; common. Europe to n. India and e. Asia, intro- 

 duced in N. America. 



Fam. 23. SALVINIACEAE Sansho-mo Ka Salvinia Family 



Floating plants with a somewhat elongate and branched axis; leaves apparendy distichous, straight in vernation; sporocarps 

 very soft and thin-walled, two or more on a common peduncle, 1-locular, the central often branched receptacle with either a 

 solitary macrospore or with numerous microspores. A small family of 2 genera. 



IA. Roots absent (some of the lower leaves finely dissected and rootlike); leaves unlobed, flat, short-petioled; stems simple 1. Salvinia 



IB. Roots present; leaves bilobed, sessile; stems pinnately branched, sessile 2. Azolla 



1. SALVINIA Adans. 



Sansho-mo Zoku 



Small floating plants; leaves ternate with two lateral, foliar, green, entire, flat blades and a third finely dissected and sub- 

 merged, the foliar structure simulating roots; sporocarps short-peduncled, on the floating leaves, globose or nearly so; micro- 

 sporangia numerous; megasporangia few, each maturing only one megaspore. About 10 species, mostly in tropical America and 



Africa, few in Eurasia. 



1. Salvinia natans (L.) All. Marsilea natans L.; S. euro- 



paea Desv. Sansh6-mo. Stems 5-10 cm. long, loosely 



branched, densely leaved, the two lateral foliar blades herba- 

 ceous, pale green, spreading, slightly imbricate, soft, elliptic to 

 oblong, 8-15 mm. long, 6-10 mm. wide, flat or very slightly 

 folded, pinnately arranged, rounded at apex, slightly cordate 



to rounded at base, short-petiolate, entire, with tufts of minute 

 bristlelike hairs on upper surface, soft-puberulent beneath, the 

 submerged leaf finely dissected and rootiike; sporangia of two 



kinds, fascicled, globose, pubescent. Sept.-Nov. Ponds and 



paddy fields in lowlands; Honshu, Shikoku, Kyushu; com- 

 mon. Europe to India and e. Asia. 



2. AZOLLA Lam. Aka-ukikusa Zoku 



Small floating mossUke plants; roots simple, unbranched; stems pinnately branched, densely leafy; leaves 2-lobed, imbricate; 

 sporocarps in pairs on the first leaf of a lateral branch, covered by the hoodUke upper lobe of the leaf, the smaller ones at base 

 with a single macrospore, the larger ones globose, with a basal placenta and many pedicellate microsporangia bearing masses of 

 microspores. About 6 species. 



lA. Leaves about L5 mm. long; plant prominently papillose, especially on the axis and lower part of leaves \. A. imbricata 



IB. Leaves about 2 mm. long; plant neady smooth or obsoletely papillose on leaves 2. A. japomca 



1. Azolla imbricata (Roxb.) Nakai. Sahnnia imbricata 



Roxb. ex Griff. Aka-ukikusa. Small reddish herb about 



1 cm. long, deltoid or rounded in outline; stems or main a-xis 



closely branched, papillose, densely leafy, few-rooted; leaves 

 sessile, 2-lobed, papillose, especially toward the base, deltoid- 

 orbicular, about 1-1.5 mm. long, very obtuse to rounded at 



