256 MR. MIERS ON THE STRUCTURE OF THE SEED 



that of the arillode, as indicated by the interesting researches of Dr. Planchon, requires 

 to be confirmed by a series of more extensive and careful observations, before it be admitted 

 as a settled fact. The most instructive and conclusive evidence of the origin and subse- 

 quent extraneous growth of the arillus over the ovule, has been adduced by Cambessedes* ; 

 he found among the ripe seeds of Casearia grandiflora many that were incomplete ; and 

 here, although the anatropal ovule showed itself in a state of complete abortion, the 

 arillus had grown over it to its full state of development, proving that where the ovule 

 had ceased to grow, the increment of the funiculus was not stopped in its progress of 

 extraneous production. 



Among the instances cited and figured by Dr. Planchon of the development of the 

 arillode, is that of Clusia flava, where he describes its ovules as presenting two short 

 cupulary membranaceous appendages, one covering the fourth part of the ovule, the other 

 much shorter and superimposed ; and while he inquires, whether one of these cups be due 

 to an expansion of the funiculus, and the other of the exostome, he seems inclined to 

 infer that both proceed from an enlargement of the foramen of the ovule. Such an 

 inference is opposed to the facts described in the foregoing pages, but his observation is 

 worthy of attention, although it is more probable that the appearances he describes are 

 those of a true arillus in progress of its development, the exterior swelling being perhaps 

 that enlargement which I have described as the stipitate foot of the arillus. According 

 to the views of Dr. Planchon, the exterior coating existing in the seeds of the Clusiece 

 must be a true arillus, because the micropyle, which I have mentioned as existing near 

 the hilum of the testa, is wholly covered by that envelope. It is proper to notice that 

 Cambessedes distinctly asserts that the seed of Clusia Criuva is enveloped in its apex by a 

 scarlet cupuliform arillus, in the work last referred to (p. 317. pi. 65. fig. 8), where it is 

 figured upon the extremity of the seed contrary to that of the hilum, and connected with 

 it by a raphe : this assuredly must be an error, made perhaps in transcribing the notes of 

 St. Hilaire, who by such swelling probably intended to figure the cupuliform caruncular 

 process surrounding the diapyle, which I have shown to exist in the same position in the 

 summit of the testa : that such a mistake evidently exists, is proved by the circumstance 

 of Cambessedes having described and figured the arillus in the apex of the seed, instead 

 of being at the base, as it would have been had it been in existence. Von Martius (Nov. 

 Gen. et Sp. hi. 166) describes the ovarium of Quapoya (Schweiggera) as containing 

 " ovula basi arillo vaginata," and Endlicher, upon no other authority than the above, 

 states that the seeds of Havetia are " basi arillo subcarnoso laxe cupulseformi cincta," 

 and he assumes upon no better evidence the same in regard to those of Quapoya, which 

 in that genus Aublet affirms to be "pulpa rubra involuta." 



The facts which I have here brought together, relative to the structure of the seeds in 

 this family, must in a considerable degree change our views of the affinities of the Clu- 

 siacece. They serve to bring the Order into close proximity with the Bhizobolacece, a 

 relationship founded upon analogies in the floral structure, long ago pointed out by Cam- 

 bessedes f, but now rendered still more evident by the great similarity observed in their 



* St. Hilaire, Flor. Bras. Mend. ii. 232. pi. 126. fig. 11. 

 t St. Hilaire, Flor. Bras. Merid. i. 323. 



