250 MR. MIERS ON THE STRUCTURE OF THE SEED 



that observed in the seeds of the Clusiea?, is seen in the centre, somewhat oblique with 

 the axis, one extremity of which terminates in the minute nipple near the apex, and the 

 other in the basal speck before mentioned : this latter spot is without doubt the germi- 

 nating point of the root, the apical nipple is the plumule, the main body of the nucleus 

 must be the radicle, and the cotyledons at first sight appear to be altogether wanting ; 

 but on examining more attentively the minute nipple- shaped process, this is seen formed 

 of four diminutive fleshy imbricated scales, surrounding a central prominent point, which 

 is concealed by the two inner and larger scales ; the two outer decussating scales thus 

 separated from each other, are smaller, shorter, and placed right and left of the ventral 

 face, as in the cotyledons of the Clusiece. This structure is so minute, that it requires the 

 aid of a strong lens to distinguish it. It may be said by some, that the two outer scales 

 form part of the plumule, and in such case the embryo would be truly acotyledonous ; 

 but it appears to me that they ought to be considered as the real cotyledons, not only 

 from analogy, but because they agree in position with the cotyledons found in the Clusiece, 

 with their commissure directed to the ventral face. I have elsewhere pointed out the 

 analogy of this structure to that of Caryocar, and it constitutes a curious physiological 

 fact. The absence of cotyledons has long been recorded in plants of a low order of deve- 

 lopment, and is known to occur also occasionally in exogenous plants among those which 

 are almost leafless, such as Cuscuta, Vohiria, &c, whence it has been argued, that the 

 abortion of the cotyledons in the embryo is indicative of the future absence of leaves in 

 the plants produced by the growth of such seeds. In the case of the Clusiacece, however, 

 where the floral structure is of the highest order of development, belonging frequently to 

 the largest trees of the tropical forests of both hemispheres, with copious foliage, large 

 fleshy leaves, and rich in mucilaginous juices, the absence of cotyledons in the seed, or 

 their reduction to microscopical proportions, offers an anomaly suggestive of many con- 

 siderations upon the nature of the organs of vegetable reproduction. 



This same internal structure of the seed occurs in every instance I have examined, and 

 is confirmed by all the evidence obtainable from recorded authority, so that little doubt 

 can exist that it is constant throughout the Order, with the exception of genera, which, 

 for reasons to be mentioned in another place, I propose to exclude from the family. The 

 evidence here alluded to exists in the drawings of Gaertner, to which I have already 

 referred; in the rough sketch given by Plunder in his ' PI. Amer.' tab. 257. fig. g, h, i, 

 which shows a similar structure in the seeds of Mheedia lateriflora ; Dr. Graham also thus 

 describes the seeds of Hebradendron gambogioides, "cotyledons thick, cohering in an 

 uniform cellular mass, radicle central, filiform, slightly curved," a structure which, though 

 described in other terms, is substantially the same organization that I have related ; Dr. 

 Wight, in his admirable ' Icones,' gives other examples of a similar structure, in plates 118, 

 192 and 960 ; and Dr. Roxburgh exhibits the same facts in his ' Coromandel Plants.' 

 These are the only positive details I find upon record, except the analysis of Calophyllum, 

 to which I will revert at another time. All accounts therefore confirm the constant pre- 

 sence of that peculiar development in the axis of the solid nucleus of the seeds of the 

 Clusiacece, which I have characterized as the neorhiza of the embryo ; for our decision 

 upon this point will determine the nature of the other parts of the nucleus, to which such 



