RUTALES.] 



PODOSTEMACE.*:. 



483 



Acrogens than another it is this, which, with the habit of Liverworts and Scale- 

 mosses, has wholly the structure of flowering plants. According to Bongard, the 

 species have neither spiral vessels nor stomates ; the latter would of course be absent, 

 on account of the submersed habits of the species of Mourera to which his observations 

 chiefly apply. And Mr. Griffith confirms his statements as regards his two Indian 

 Podostemons. But although Podostemads must be considered to pi'escnt a very 

 strongly marked approach to flowerless plants in some i-espects, yet we must look for 

 some more immediate relation. This I formerly thought might be found with Peppers, 

 or Callitriche ; Meisner suggests Hornworts. But if we regard hermaphrodite flowers, 

 hypogynous stamens, and an exalbuminous embryo as the most important features in 

 these plants, our views of its affinity will take a very different direction, and we can 

 scarcely fail to suspect an approach to Waterpeppers, whose manner of life is in some 

 respects similar. In fact, upon comparing the two Orders, we find that they are 

 otherwise much aUke, except that Podostemads are more incompletely formed in the 

 floral envelopes, and seem to want the capitate stigmas of that Order. Both have 

 2 -celled anthers burstmg inwards longitudinally, and a separable placenta bearmg 

 numerous anatropal seeds. It seems, therefore, probable that Podostemads stand in 

 the same relation to Waterpeppers as Hippurids to Onagrads, and Lemnads to Arads. 



Natives of rocks, in rivers, still waters, and damp places in South America and 

 the islands ofif the east coast of Africa ; 1 species is found in North America, 2 m the 

 East Indies. 



Some species of Lacis yield, when burnt, a considerable quantity of salt from their 

 -SchoniburaJc. 



GENERA. 



Mniopsis, Mart. 



Crenias, Spreng. 

 Hydrobryum, Endl. 

 Podostemon, L. C. Rich. 



Dicrceia, Thouars. 

 Mourera, Auhl. 

 Neolacis, Cham. 

 Marathrum, H. B. K. 



Lacis, Lindl. 

 Tristicha, Thouars. 



Dufourea, Bory. 



Philocrene, Bong. 



Hydrostachys, Thouars. 

 Halophila, Thouars. 

 ? Lemnopsis, Zippel. 



Numbers. Gen. 9. Sp. 25. 



Ilaloragea. 

 Position. — Elatinacese. — Podostemace.b, — Piperaceee. 



Ma7'chantiac€ce. 



Ii2 



