466 lviii. lythrace^: (hiern). [Eotala. 



2. ROT ALA, Linn. Mant. 175. 



Calyx campanulate or rarely tubular, usually hemispherical in fruit, 

 4- rarely 5-lobed, in one species with intermediate acicular cornua, 

 usually not accrescent. Petals as many as calyx-lobes or 0, usually 

 minute, obovate, not corrugated in the bud. ^ Stamens 1-5 usually 4, 

 not more numerous than the calyx-lobes ; filaments filiform. Ovary 

 1-4-celled, free, many-ovuled, sessile ; style short or long; filiform ; 

 stigma capitate. Capsule 2-4-valved, many-seeded, usually exceeding 

 the calyx-tube ; placenta usually compressed ; seeds numerous ; embryo 

 straight with short radicle. — Glabrous herbs growing in wet places or 

 even in water. Leaves opposite or verticillate, flat ; flowers axillary, 

 sessile or subsessile, solitary or few together, bibracteate, in R. num- 

 mularia (aDd perhaps in other species) dimorphous. 



Scattered over the Tropics of the whole world. 



Flowers solitary. 



Calyx whitish, scarious (or sometimes purplish in R.filiformis). 

 Capsule 4-valved. 



Calyx tubular, accrescent 1 . R. elatinoides. 



Calyx campanulate, not accrescent 2. R. tenella. 



Capsule 3 valved. 



Flowers pentamerous ; leaves more or less whorled . . 3. R. verticillaris. 

 Flowers tetramerous ; leaves always opposite. 



Calyx cornuate 4. R. decussata. 



Calyx not cornuate 5. R. stagnina. 



Capsule 2 valved. Stamens 2 ......... 6. R.filiformis. 



Calyx rose-coloured, membranous. Stamens 4. (Mirkooa.) 

 Leaves opposite. 



Petals small; capsule 2-valved 7. R. fontinalis. 



Petals large ; capsule 4-valved ......... 8. R. nummularia. 



Leaves whorled 9. R. myriophylloides. 



Flowers 1-4 together 10. R. serpiculoide*. • 



1. R. elatinoides, Hiern. Annual, ascending, nearly simple, slen- 

 der, subterete, rooting at the base, 2-4 in. high. Leaves ovate-oblong, 

 decussate, subsessile, the upper ones sessile shorter and cordate or 

 subcordate at base, ^-J in. long ; lower internodes longer than the 

 leaves. Flowers solitary, subsessile in the axils of upper leaves, each 

 with 2 subulate bracts at base. Calyx at first campanulate, cylindrical 

 and accrescent in fruit, semipellucid, 8-veined, 4-lobed, not cornuate ; 

 lobes \-^ of the length of the calyx, deltoid or lanceolate, acute. 

 Petals. 4, oblong, violet or white, marked with reddish midrib, rather 

 exceeding the calyx-lobes. Stamens 2 or 4, inserted below middle of 

 calyx-tube, about equalling the calyx-tube. Ovary 4-sulcate, 4-celled, 

 ovoid, sessile, without hypogynous disk ; style very short, or stigma 

 subsessile. Capsule tubular, 4-celled, dehiscing by 4 valves septi- 

 fragally, enclosed in the persistent calyx ; placenta slender, tetragonal ; 

 seeds concave on one side, convex on the other. — Ammannia elatinoides, 

 DC. Monogr. Lyth. 28, t. iii. B. Ameletia elatinoides, Bl. Mus. Bot. 

 ii. 136. 



