130 Hydrocharitaceae; Triuridaceae 



5. OTTELIA Pers. Mizu-obako Zoku 



Submersed herbs; leaves radical, periolate, lanceolate to cordate; scapes radical, elongate; flowers solitary in a spathe terminal 

 on the scape, sessile, bisexual; outer perianth-segments 3, linear to oblong, the inner larger, petaloid, obovate or rounded, short- 

 appendaged at base; fertile stamens 3, the anthers erect; staminodes 6-15; ovary oblong, beaked; styles 6-9, linear, bifid; ovules 



numerous; fruit oblong, enveloped by a spathe; seeds numerous, small, hairy. About 10 species in tropical and subtropical 



regions. 



1. Ottelia alismoides (L.) Pers. Stratiotes alismoides entire or obscurely dentate; scape elongate, the spathe to 4 



L.; O. japonica Miq.; O. alismoides var. japonica (Miq.) Ko- cm. long, with or without prominent crispate wings; sepals 



mar. ^Mizu-obako. Submersed green annual without rhi- linear-lanceolate, obtuse, green; petals thin, ovate-orbicular, 



zomes; leaves radical, rosulate, thin, long-petioled, oblanceo- much longer than the sepals, white to reddish; ovary sessile 



late in the vernal, broad-ovate or ovate-cordate in the summer within the spathe. Aug.-Oct. Ponds and paddy fields; 



ones, 10-25 cm. long, 2-15 cm. wide, obtuse, 5- to 9-nerved, Honshu, Shikoku, Kyushu. India and Australia. 



6. HYDROCHARIS L. Tochi-kagami Zoku 



Aquatic monoecious herbs; stems elongate, leafy; leaves floating or raised above the water, rounded to reniform, entire, 

 long-petiolate; scapes axillary; staminate flowers 2 or 3 in a spathe, the outer perianth-segments 3, sepallike, the inner 3 petaloid, 

 white, delicate, the stamens 6-18 with 3-6 staminodes; pistillate flowers solitary in a spathe, long-pedicelled, with perianth- 

 segments similar to those of the staminate, with 6 staminodes, the ovary ovoid, 6-locular, with 6 linear bifid stigmas; fruit 

 ovoid to oblong, fleshy; seeds numerous. Two species in Eurasia and Australia. 



1. Hydrocharis dubia (Bl.) Backer. ? Pontederia duhia green; petals rounded-cunea,te, thinly membranous, white, yel- 



Bl.; H. asiatica Miq. Tochi-kagami. Aquatic peren- low at base, 12-15 mm. long and as wide; stamens 6-9, yel- 



nial; stems branched, leafy at the nodes; leaves rounded- low, with short-pilose filaments, the anthers introrse; stigmas 



cordate, 4-8 cm. long and as wide, long-petiolate, rounded at 6, yellow, deeply bifid; fruit globose. Aug.-Oct. Ponds; 



apex; flowers raised above the water; sepals narrowly oblong, Honshu, Shikoku, Kyushu; common.-^ se. Asia and Australia. 



Fam. 40. TRIURIDACEAE Hongo-so Ka Triuris Family 



Delicate, white, pink, or reddish, saprophytic herbs with leaves reduced to scales; stems simple, loosely scaly; flowers bisexual 

 (or plants monoecious), small, pedicelled, bracteate, in a terminal raceme or umbellate; perianth-segments 4-8, lanceolate, 

 valvate in bud; staminate flowers with 2-6 stamens, the anthers free or impressed in a thick disc, 2- to 4-locular, the reduced 

 pistil absent or 3; pistillate flowers with or without staminodes, with numerous carpels, sessile on a receptacle, 1-locular, 



1-ovuled, the style terminal or ventral, persistent, the stigma acute or clavate; ovules erect, anatropous; fruit an achene. Four 



genera, with about 40 species, mosdy in the Tropics, 1 genus in Japan. 



1. SCIAPHILA Bl. HoNGo-so Zoku 



Saprophytic herbs without chlorophyll, monoecious or dioecious; stems simple, filiform or very slender, loosely scaly; flowers 

 small, unisexual or polygamous, in racemes, the pedicels bracteate at base; perianth-segments 3-8, narrow, sometimes hairy at 

 apex, inflexed in bud; anthers sessile or with very short filaments attached on a small receptacle; carpels numerous, free, anterio- 



posteriorly dehiscent, the style on ventral side of the carpel; seeds erect, ellipsoidal, small. ^Many species, in tropical forests 



of Asia and northern S. America. 



lA. Perianth-segments 4, broadly lanceolate, with few hairs at tip; lower flowers bisexual 1. S. takfiktimensis 



IB. Perianth-segments 6, broadly lanceolate to linear, glabrous; flowers unisexual. 



2A. Very delicate herbs, with loose 4- to 15-flowered racemes; pedicels filiform, about 3.5 mm. long, longer than the flowers; staminate 



flowers with reduced pistils, the perianth-segments broadly lanceolate, acuminate 2. 5. japonica 



2B. Delicate herbs with 3- to 8-flowered racemes; pedicels shorter than the flower, 2-4 mm. long; staminate flowers without reduced 

 pistils, the perianth-segments linear 3. S. tosaensis 



1. Sciaphila takakumensis Ohwi. Takakuma-so. (Makino) T. Ito; Parexuris japonica (Makino) Nakai & F. 



Very delicate herb; stems 5-10 cm. long, erect, loosely few- ^Aaeka.wz; Andruris japonica {iAskino) Giesenh. Hongo-s6. 



scaled; racemes loosely 4- to 10-flowered, with minute, ovate. Stems 3-8 cm. long, with few appressed scales; racemes loosely 

 obtuse bracts, the pedicels filiform, 2-10 mm. long, slightly 4- to 15-flowered, with minute, linear-lanceolate, acuminate 

 curved; perianth-segments of bisexual flowers 4, about 1 mm. bracts; staminate flowers about 2 mm. across, with 3 reduced 

 long, acute and with few long hairs at apex; stamens 4; carpels carpels, the perianth glabrous, the segments broadly lanceo- 

 about 20, oblong; style clavate, attached slighdy above the late, acuminate; stamens 3, the anthers sessile, 2-locular; pistil- 

 base on ventral side of the carpel, about half as long as the late flowers about 1.5 mm. across, with 6 ovate, acute, glabrous 

 carpel; carpels 0.8 mm. long at maturity, the seeds dark brown, perianth-segments, the carpels numerous, the style attached 

 glossy. Kyushu (Mount Takakuma) ; very rare. above the middle on the ventral side, filiform, 0.8 mm. long, 



2. Sciaphila japonica Makino. Seychellaria japonica longer than the carpel; carpels about 0.7 mm. long, in a glo- 



