370 Linnaan Society : — 



Royal Gardens at Kew, in various stages of advancement. His view 

 of the embryo is, that the plumule is enclosed within two large 

 amygdaloid cotyledons, with well-defined margins, which are distinct 

 down to the attachment of the base of the plumule, or very nearly 

 so ; and there is also an obvious tendency to form a radicle, so that 

 the embryo appears to conform fully to the ordinary dicotyledonous 

 type. Then follows the membranaceous envelope and four leaves 

 successively, which are alternate with the cotyledons, and in most 

 cases there is a slight attempt to produce a fifth. The membranous 

 envelope, or proper membrane of the plumule, consists entirely of 

 cellular tissue, and has indistinctly the appearance of a leaf alter- 

 nating with the first leaf above it. The first two leaves having 

 laminae are elevated in the young stem of the plumule, so as to be 

 removed to some extent from the cotyledons, while the proper mem- 

 brane arises from its very base, and might be described perhaps as 

 being attached to the line of junction between the young stem and 

 cotyledons. It can have no connection with the first leaf of the 

 plumule, a considerable portion of the axis intervening between 

 them. Supposing it to be a stipule, it must be compounded of two, 

 and those belonging to the cotyledons. This, however, the author 

 thinks, will not be regarded as probable ; he considers it without 

 doubt as a rudimentary leaf of the plumule itself, for which opinion 

 he gives several reasons. It is further remarkable that all the re- 

 maining four leaves of the plumule are furnished with laminae, differ- 

 ing in this respect, Mr. Clarke observes, from those of the stem, where- 

 only one leaf in three ever produces a lamina. Of these four leaves 

 of the plumule the first is without stipules ; a farther proof, in Mr. 

 Clarke's opinion, that the proper membrane is not to be regarded as 

 a stipule. Of the three succeeding leaves, the intra- axillary stipule 

 of each, on being laid open, is found to contain the succeeding leaf. 

 This stipule Mr. Clarke regards as compounded of two, one origina- 

 ting on each side of the petiole, united by their membranous margins 

 within the axil of the leaf, as in Pontederia and Potamogeton. As 

 regards the foliage of the plant, Mr. Clarke states that according to 

 his view, three leaves only are produced on each node, and are 

 attached so nearly on a parallel, that did they not successively enclose 

 each other, they could not be distinguished from opposite leaves ; 

 of these the two outermost of each whorl consist only of membranous 

 scales, without any rudiments of stipules, completely surrounding the 

 third and perfect leaf. This leaf having a lamina, should, Mr. 

 Clarke states, in common with those in the upper part of the plumule, 

 have a large intra-axillary stipule, enclosing the terminal bud or 

 growing-point, and this he finds to be obviously the regular struc- 

 ture. The flower appeared in one instance not to be terminal, but 

 to be produced from the axil of the second scaly leaf, while the buds 

 in the axils of the leaves with laminae were leaf-buds. On the sub- 

 ject of affinity, Mr. Clarke thinks that the Nymphseal alliance, as 

 usually limited, has no very near relationship except with Ranun- 

 culaceie ; but that much analogy exists between it and some Endo- 

 genous families, and that it may also be connected with Crypto- 

 gamce, through Ceratophyllum and Chara, the embryo of Ceratophyllum 



