STRUCTURE.] SALVINIA. AZOLLA. 103 



The following is the substance of his descriptions of Salvinia 

 and Azolla : 



Salvinia. Male organs ? articulated hairs on the stalks of 

 the ovule, each joint containing a nucleus and a brownish 

 fluid ; Ovula nearly sessile, concealed by the roots, and partly 

 covered with hairs ; tegument open at the top ; mature repro- 

 ductive organs solitary, or in racemes of 3-5, about the size 

 of a pea, covered with brown rigid hairs. The upper ones of 

 each raceme, (or lowest as regards general situation), contain 

 innumerable spherical bodies, of a brownish colour and reti- 

 culated cellular surface, terminating capillary simple fila- 

 ments. These again contain a solid whitish opaque body. 

 The other, which occupies the lowest part of the raceme, and 

 which is the first and often the only one developed, is more 

 oblong, containing 6-18 larger, oblong-ovate bodies, on short 

 stout compound stalks : colour brown, surface also reticulated. 

 Each contains a large, embossed, opaque, ovate, free body, of 

 a chalky aspect : it is three-lobed at the apex, and contains 

 below this a cavity lined by a yellowish membrane, filled with 

 granular and viscid matter and oily globules. 



Azotta. The growing points present a number of minute 

 confervoid filaments, the assumed male organs, which at cer- 

 tain periods may be seen passing into the foramen, the ovula 

 becoming resolved into their component cells within the 

 cavity of that body ; organs of reproduction in pairs, attached 

 to the stem and branches, one above the other, concealed in 

 a membranous involucrum ; ovula atropous, oblong-ovate, 

 with a conspicuous foramen and nucleus, around the base of 

 which are cellular protuberances ; capsules of each pair either 

 difform, in which case the lowest one is oblong-ovate, the 

 upper globose, or both of either kind, generally perhaps the 

 globose, presenting at the apex the brown remains of the 

 foramen, and still inclosed in the involucrum; upper half 

 generally tinged with red ; the oblong-ovate capsule opens by 

 circumcision; with the apex separate the contents, which 

 consist of a large yellow sac contained in a fine membrane, 

 the remains of the nucleus (or the secondary capsule). The 

 sac is filled with oleaginous granular fluid, and surmounted 

 by a mass of fibrous tissue, by which it adheres slightly to the 



