66 NAIADES. [Cl. 1. 



(61) is a stalked globular Capsule, fig. 101, 104, of two 

 valves, either naked, or bound by a trans verse elastic ring. 

 Seeds very minute, readily germinating, and so abun- 

 dant, that many a species, if its possible increase were 

 uninterrupted for 20 years, might cover the wholeearth. 

 The forms and situations of the Sori. and the direction 

 in which the Involucrum separates, afford generic cha- 

 racters, unknown when Jussieu published. 



Polypodium has no Involucrum ; Aspldium a round- 

 ed one ; Pterls a continuous one, separating inward ; 

 Lindscea the reverse. 



Ord.6. NAIADES. " Calyx either entire or divided, 

 superior or inferior, rarely wanting. Stamens definite, 

 perhaps perigynous (97). Germen superior or infe- 

 rior, solitary or four-fold. Style 1, rarely 2, to each 

 Germen, or wanting. Stigma one or several. Seeds 

 solitary, or several, either naked and superior, or in- 

 closed in a Pericarp which is either superior or infe- 

 rior. Leaves mostly opposite or whorled. Flowers 

 in some perfect (65), in others monoecious or dioe- 

 cious. Plants all herbaceous, and, except Saururus, 

 aquatic." The uncertainty of this Order has been 

 already noticed, (92), and the characters, above given, 

 have so many ambiguities as to amount scarcely to 

 any thing. The Genera are, Hippuris, fig. 252, Chara, 

 Ceratophyllum, Myriophyllum, fig. 251, Naias, Saw- 

 rurus, Aponogeton, fig. 134, Potamogeton, fig. 135, 

 Ruppia, Zannichdlia, Callltriche and Lemna, fig. 1 36. 

 Naias, Lemna, and Chara, are judged by Mr. Brown 



