Linnaan Society. 289 



vature in the embryo of the latter being regarded as analogous to 

 the position of the raphe in the two former. 



6. The position of the raphe next the placenta is well known to 

 be the ordinary condition in erect anatropal ovules, and on this head 

 the author enters into no details. 



Mr. Clarke then proceeds to consider the causes by which these 

 (Hfterences in the position of the raphe may be produced. 



1 . He adopts the opinion (first demonstrated by Mr. Brown) that 

 u single ovule pendulous with raphe aversa is the result of an erect 

 ovule pressed or growing downwards from the elongation of the 

 cavity of the ovarium in that direction, while its upper part remains 

 stationary ; but suggests that it is only when an erect ovule has the 

 raj)he properly next the placenta that it has raphe aversa, when it 

 thus becomes pendulous. And looking to their affinities, he thinks 

 it not improbable that all pendulous orthctrojial ovules should be 

 referred to the same cause. 



2. He believes that a single pendulous ovule with the raphe lateral 

 is an ovule originally extending horizontallj'^ from the placenta with 

 the raphe lateral, as in Ranunculacece and Cucurbit acece, and sub- 

 sequently pressed downwards as in the former case. 



3. He maintains that a single pendulous ovule with the raphe next 

 the placenta is the only true pendulous ovule, with the exception of 

 pendulous carnpylotropal and amphitropal ovules with the foramen 

 (and subsequently the radicle of the embryo) turned away from the 

 placenta. 



4. He conceives that one or two erect ovules with the raphe turned 

 away or obliquely away from the placenta result from pendulous 

 ovules pressed upwards by the elongation upwards of the cavity of 

 the ovarium ; and adduces in support of this opinion the pendulous 

 ovules of Geissoloma contrasted with the erect ovules of Pencea, the 

 erect ovules of Calytrix compared with the pendulous ovules of the 

 neighbouring families, and the pendulous ovules of Calycerece com- 

 jtared with the erect ovules of Compositts, provided further observa- 

 tion should substantiate his belief that in the last-named family the 

 TaT)he is really turned away from the placenta. Such ovules he 

 would term spurie erecta, in contradistinction to the opposite case 

 to which Sprengel has applied the term spurie pendula. 



5. He considers that a single ovule erect with the raphe lateral is 

 a horizontal ovule spontaneously growing or pressed upwards by the 

 corresponding development of the ovary ; in proof of which he cites 

 the fact that Trianthema micrantha has two seeds in a horizontal 

 position, with the radicle lateral, while T. decandra has two erect 

 seeds one above the other, with the radicle also in both cases 

 laternl. 



6. He considers one or two erect ovules with the raphe next the 

 placenta (which seems general in Endogenous plants, and is frequent 

 in all the divisions of Exogenous) as for the most part truly erect ; 

 although this position may sometimes be derived from horizontal 

 ovules pressed u])wards or spontaneously growing erect, the funi- 



Ann. ^ Mag. N. Hist. Ser. 3. Vol. x. 19 



