LYTHBARIACEjE. 



441 



(iampanulate receptacle, thin and membranous, is marginally con- 

 tinuous with the six triangular valvate lobes of the calyx, glandular 

 at the summit ; in the intervals are an equal number of accessory 

 teeth, the origin of which is the same as in Salicaria. To these 

 teeth correspond an equal 



number of small obtuse Ammannia [FepUs) portuU. 



very caducous petals, which 

 are sometimes entirely ab- 

 sent. . Much lower, on the 

 internal surface of the re- 

 ceptacle, are inserted six 

 alternipetalous perigynous 

 stamens formed, each, of an 

 enclosed filament and a bi- 



locular, introrse, didymous anther, dehiscing by two longitudinal 

 clefts. The gynsecium is free, formed of an enclosed two-celled ovary, 

 surmounted by a short style with capitate stigmatiferous apex. In 



Ammannia [Svffrenia) filiformis. 



Fig. 418. Flower {\). 



Fig. 419. Long. sect, 

 of flower. 



Fig. 420. Flower (f). 



Fig. 421. Diagram. Fig. 422. Long. sect, of flower. 



the internal angle of each cell is a placenta supporting an indefinite 

 number of anatropous ovules. The fruit, enclosed in the persistent 

 receptacle, is a membranous and polyspermous capsule, the seeds of 

 which contain, under their thick coats, a fleshy embryo, with oval 

 cotyledons and short radicle. In southern Russia there is a Peplis 

 called P. horysthenica,^ which differs from P. portula only in the 

 greater length of its style. A genus has been made of it under the 

 name of Middendorffia.^ Another Peplis, in the United States, P. 

 diandra,^ type of the genus BidipUs,'^ is quite similar to our P. 



^ Bess, ex Spbeng. Si/st. ii. 135. — Ammania 

 iorysthemca DC. Frodr. iii. 78, n. 10. 



2 Teautv. Diss, de Middendorffia, Mdm. Sa/v. 

 itr. Ac. Petersb. iv. 489, t.4.— Waip. Rep. v. 673. 



' NvTT. ex DC. Prodr. iii. 77, n. 4. — Ptolina 



aquatica Nutt. (ex DC). 



* Eapin. Atlant. Journ. (1833)' n. 6, p. 23.— 

 Endl. Gen. li'll.—B. H. Gm. Ill, n. 3.— 

 Sypobrichia M. 0. Curt. Torr. et Gr. Fl. N.- 

 Amer. i. 479. 



