CCXXI. PODOSTEMACEiE. V37 



CCXXI. PODOSTEMACEJE} 



(PoDOSTEMEiE, Richard. — Podostemaoe^, Lindl.) 



[Ploweks ^ or diclinous. Perianth or simple. Andkcecium hypogynous, 

 1-S-seriate. Stamens definite or indefinite. Ovaet 1-3-ceUed ; stigmas 1-3, sessile 

 or on a style ; ovules numerous in the cells. Capsule septicidal. Seeds minute, 

 albuminous. — Aquatic hbebs, sometimes frondose, often resembling Algse or Hepaticese. 



Watek-plants, with a distinct simple or branched stem and leaves, or with 

 these confluent into broad or narrow Alga-like fronds. Ineloeescence various, 

 often scapose ; scajpes 1- or many-flowered, arising from a tubular sheath or involucre, 

 or naked. Flowers unisexual or 5 , naked or monochlamydeous, usually enclosed 

 in a spathaceous marcescent involucre, which is at first closed, then bursts ; mouth 

 2- or more- lobed. Perianth 0, or calycine or petaloid, 3-lobed or -partite, mem- 

 branous, marcescent. Stamens definite or indefinite, free or monadelphous, erect ; 

 filaments linear flat or membranous, marcescent; anthers ovate-oblong or linear, 

 2-lobed, dorsifixed, dehiscence longitudinal; pollen powdery, globose didymous or 

 3-gonous. Staminodes filiform or subulate, as many as and alternate with the stamens, 

 or inserted with them or outside them, or more than them, or 0. Ovary free, sessile 

 or stipitate, central or excentric, smooth or costate, 1-3-celled ; style cylindric or ; 

 stigmas 2-3, simple or dilated or laciniate or toothed, rarely 1 capitate ; ovules 

 numerous in each cell, attached to thick axile or slender parietal placentas, ana- 

 tropous. Capsule 1-3-celled, septicidally and septifragally 2-3-valved, many- 

 seeded ; valves equal and persistent, or unequal, the smaller deciduous. Seeds 

 microscopic, compressed ; testa mucilaginous ; tegmen membranous ; albumen 0. 

 Embryo straight, oily ; cotyledons erect ; radicle very short, obtuse. 



Teibe I. Htdeostachte^. — Mowers naked, dioecious. Ovary 1-celled ; carpels 2, alter- 

 nating with bracts ; placentas linear, parietal. Hydrostachys. 



Teibe II. E upodostemace^. — Flowers g witbont perianth and enclosed in an involucre. 

 Ovary 2-3-celled, with axile placentas, or l-ceUed with a central placenta. Mourera, Jpinagia, 

 Bicrcea, Podostemon, Hydrohryum, Castelnavia, Tristiclia. 



The affinities of Podostemacem are most obscure. I have suggested that they are reduced forms of 

 Zmtihdarinecs or Scrophularinem. The decidedly dicotyledonous embi^o removes them from all the 

 Monocotyledons with which they have been compared. Lindley has suggested Fiperacets and CaUi- 

 triche, Meissner Ceratophyllece ; more lately Lindley allies them undoubtingly to Elatine<s. 



Podostemaeea are natives of rocky river-beds in the tropics ; Sydrostachys is Madagascarian ; Bicrma 

 and Tridicha are Asiatic, Madagascarian, and American. One Podostemon inhabits temperate North 

 America ; the rest of the family are chiefly American, except Sydrohryum, which is Indian. 



The only known use of the family is that the South American Indians make some use of their saline 

 ashes. — Ed.] 



' This order is omitted in the original. Its characters are taken from Tulasue's monograph.— Ed. 



3b 



