650 



Lythraceae 



cordate and semiclasping at base; spikes erect, terminal, 20-35 

 cm. long, the bracts ascending, broadly lanceolate to deltoid- 

 ovate, 5-12 mm. long; flowers rose-purple, 1-3 in axils, cymose; 

 peduncles and pedicels very short; calyx-tube 5-8 mm. long, 

 12-ribbed, with 6 deltoid teeth, the appendage spinehke, erect, 



1.5-2 mm. long; petals cuneate-oblong, 7-8 mm. long. Aug. 



Wet places in lowlands and hills; Hokkaido, Honshu, Shikoku, 



Kyushu; rather common. Europe, N. Africa, Afghanistan, 



n. India, China, and e. Asia. 



2. Lythrum anceps (Koehne) Makino. L. virgatum 

 sensu Miq. non L.; L. salicaria var. anceps Koehne; L. salicaria 



subsp. anceps (Koehne) Hara Miso-hagi. Resembling 



the preceding but more slender and nearly glabrous; leaves 

 usually acute, acute to broadly cuneate at base, sessile or sub- 

 sessile, not clasping; floral bracts usually spreading, broadly 

 lanceolate to ovate-oblong; appendages of calyx-tube short, 0.5- 



0.7 mm. long, spreading. Wet places in lowlands and hills; 



Honshu, Shikoku, Kyushu. ^Korea. 



4. ROTALA L. 



KiKASHIGUSA ZOKU 



Glabrous annuals or perennials; leaves opposite or verticillate, sessile; flowers small, 3- to 6-merous, usually sessile, solitary in 

 axils or in terminal spikes or panicles, 2-bracteolate at base; calyx nearly globose, campanulate, or urceolate, 3- to 6-lobed, often 

 with a spinelike appendage between dae lobes, with annular nectary glands at base; petals persistent, deciduous, or absent; 

 stamens 1-6, opposite the calyx-lobes; ovary incompletely 2- to 4-locular; ovules few to many; style absent or conspicuous; 



capsules septicidally dehiscent, cartilaginous, the pericarp with minute transverse striae; seeds minute. About 40 species, in 



the Tropics and warm temperate regions. 



lA. Leaves verticillate, shortly truncate or minutely bimucronate at apex. 



2A. Flowers apetalous; stamens 2 or 3; leaves 3- or 4-verticillate 1. R. mexicana 



2B. Flowers petaliferous; stamens 4; leaves 5- to 12 -verticillate 2. R. hippuris 



IB. Leaves opposite, obtuse, rounded, or subacute at apex. 

 3A. Flowers or fascicles of flowers axillary, white to reddish. 



4A. Leaves broadly linear to broadly lanceolate-oblong, 6-25 mm. long, obtuse or subacute Z. R. leptopetala var. littorea 



4B. Leaves obovate-oblong, 5—10 mm. long, rounded at apex. 



5A. Leaves with translucent cartilaginous margins; styles 0.5-0.7 mm. long, slender, distinct, with a capitate stigma; stamens 4. 



4. R. indica 



5B. Leaves without translucent cartilaginous margins; styles shorter, with a capitellate stigma; stamens 2 5. R. elatinomorpha 



3B. Flowers in a terminal spike, red-purple 6. R. rotundifolia 



1. Rotala mexicana Cham. & Schltdl. R. apetala F. 

 Muell.; Hypobrichia spruceana Benth.; R. mexicana var. 



typica Koehne, and var. spruceana (Benth.) Koehne ^Mizu- 



MATsuBA. Glabrous reddish annual 3-10 cm. high, usually 

 creeping and branching at base, erect in upper part, rather soft; 

 leaves 3- to 4(-5)-verticillate, narrowly lanceolate to broadly 

 linear, 6-10 mm. long, 1.5-2 mm. wide, truncate and often 

 bimucronate, narrowed to a sessile base; flowers solitary in 

 axils, sessile, about 0.8 mm. long, reddish, usually 5-merous, 

 the bracteoles thinly membranous, linear, as long as the calyx; 

 calyx semigl obese in fruit, the lobes deltoid; stamens 2 or 3; 

 capsules globose, about twice as long as the calyx; style ab- 

 sent. Aug.-Oct. Paddy fields and wet places in lowlands; 



Honshu, Shikoku, Kyushu; common. The Tropics and 



warm-temperate regions of the world. 



2. Rotala hippuris Makino. Mizu-sugina. Usually 

 glabrous perennial with slender creeping rhizomes; stems erect, 

 terete, branched at base; leaves 5- to 12-verticillate, the sub- 

 merged ones filiform, 2-3 cm. long, 2-lobulate at apex, the 

 aerial ones linear, 5-10 mm. long, 0.7-1 mm. wide, obtusely 

 truncate to obscurely bimucronate at apex, scarcely narrowed 

 at base; flowers solitary in axils, sessile, the bracteoles linear, 

 shorter than the calyx-tube; calyx-tube about 0.7 mm. long, glo- 

 bose in fruit, the lobes 4, deltoid, short; petals obovate, about 

 twice as long as the calyx-lobes, retuse; stamens 4; capsules glo- 

 bose, about 1.5 nun. across; styles short and slender, the stigmas 



capitellate. Sept.-Oct. Wet places in lowlands; Honshu 



(Owari and Ise Prov.) ; very rare. 



3. Rotala leptopetala (Bl.) Koehne var. littorea (Miq.) 



Koehne. Ammannia littorea Miq. Mizu-kikashigusa. 



Erect, branched annual often ascending from base; stems 

 terete, 10-30 cm. long; leaves broadly linear to broadly lanceo- 

 late-oblong, 6-25 mm. long, 2-5 mm. wide, obtuse to subacute, 



obtuse to subrounded at the sessile base; leaves on upper 

 branches much smaller and narrower; flowers solitary in axils, 

 sessile, often reddish, about 0.7 mm. long; calyx-tube cup- 

 shaped in fruit, the lobes usually 4, very small, acuminate; 

 petals oblanceolate, as long as the calyx-tube, persistent; cap- 

 sules globose, about 2 mm. across, reddish, much exserted from 



the calyx-tube. Aug.-Nov. Paddy fields and wet places in 



lowlands; Honshu, Shikoku, Kyushu; common. The typical 



phase occurs in e. Asia to Malaysia, and s. Asia to Afghanistan. 



4. Rotala indica (Willd.) Koehne. Peplis indica WiWd.; 



Ammannia peploides Spreng.; Ameletia uliginosa Miq. 



KiKASHIGUSA. Glabrous annual; stems creeping and branched 

 at base, ascending to erect and short-branched in upper part; 

 leaves opposite, flat, obovate-oblong or obovate, sometimes 

 nearly oblong, 5-10 mm. long, 3-5 mm. wide, rounded at apex, 

 narrowed to the sessile base, with translucent cartilaginous 

 margins; leaves of short upper branches smaller; flowers soli- 

 tary in axils, sessile, the bracteoles linear, as long as the calyx; 

 calyx tubular-campanula te, about 1.5 mm. long, the lobes 4, 

 narrowly deltoid, acuminate, spine-tipped; petals small; stamens 

 4; capsules ellipsoidal, not exserted, included within the calyx; 

 styles slender, 0.5-0.7 mm. long, the stigmas capitate. Aug.- 

 Oct. Paddy fields and wet places in lowlands; Hokkaido (sw. 

 distr.), Honshu, Shikoku, Kyushu; common. e. Asia, Ma- 

 laysia, and India. 



5. Rotala elatinomorpha Makino. Hime-kikashigusa. 

 Glabrous annual; stems creeping, the branches erect 4-7 cm. 

 long, loosely leafy; leaves thin, opposite, obovate-oblong, 3-10 

 mm. long, 1.5-4 mm. wide, rounded at apex, narrowed to the 

 sessile base, without translucent cartilaginous margins; flowers 

 sessile, solitary in axils, about 1.5 mm. long, the bracteoles 

 linear, acuminate, as long as the calyx-tube; calyx-tube short- 

 cylindric, 4-angled, without appendages, the lobes 4, narrowly 



