﻿2g2 MR. J. MIERS ON THE LECYTHIDACEiE. 



vessels belonging to the branching raphe ; a solid nucleus fills the testa, covered by a 

 very thin integument ; it has no albumen, is homogeneous in substance~in fact is a 

 gigantic radicle, as in Lecytliis, with extremely minute cotyledons, situated at the ex- 

 tremity contrary to the hil um : these are generally overlooked ; but at that point two 

 converging grooves may be seen, caused by the overlapping of the edges of the minute 

 cotyledons, so smoothed by pressure as to be scarcely visible except under maceration ; 

 they are better seen in a longitudinal section of the nucleus, when beneath them a 

 roundish plumula is distinctly perceptible, from which a line extends all round, parallel 

 with the periphery, which marks the line of union between the external lamina of the 

 exorhiza and the internal neorhiza, which forms the main body of this gigantic radicle. 

 This view of the structure is confirmed by a specimen in the Kew Museum, where, in a 

 ffcrminating seed, the plumula expanding into the nascent stem is seen forcmg its 



way between the minute cotyledons, while at the opposite extremity the mammiUary 

 point of the neorhiza protrudes downwards to form the root. The account given hy 

 Berg is, that although the nucleus seems " pseudo-cotyledonous," it is in reality dicoty- 

 ledonous, adding in a parenthesis the words of Martins ^ : — " Cotyledones tamen 2 adsunt 

 plerumque ingequales, commissura arctissima sibi per transversum seminis applicitae; 

 rostellum (radicula) fere in medio semine laterale, parum conspicuum." In accordance 

 with this account, longitudinal sections are given to express his meaning ^ where 2 large 

 superposed cotyledons, horizontally in contact, show in a chink on one side a small 

 imbedded radicle at the point of their union. Any one who cuts through a Brazil nut 

 will see that Berg's description is wholly incorrect ; and it is deeply to be regretted that 

 so palpable a mistake on this important point of structure should mar the value of the 

 copious analyses in a work of such beautiful execution as the ' Plora Brasiliensis. I 

 may add, also, that my view of the structure of the embryo is essentially the same as that 

 given by Bichard I 



The genus Zecythis (Plate XXXIY. a) is numerous in species ; but more than one half 

 of those referred to it by authors belong to other genera, as 1 propose to demonstrate ; the 

 details of its floral and carpological structure here given apply therefore to this genus 

 as now restricted for the first time. These species form some of the most ornamental 

 trees of the forests, being generally from 20 to 60 feet high, with a copious foliage 

 solid timber of considerable use, with a soft inner bark of some thickness, easdy de- 

 tached, and which, beaten while fresh, resolves itself into numerous distinct membranous 

 sheets. Poiteau relates* that he counted as many as 110 of these laminse in a s 

 flake of the bark ; it is called estopa (oakum) in commerce, and is applied to many 

 useful purposes. The leaves of the true LecytUs, compared with those of the exc 

 species, are generaUy smaller, of much thinner texture, of a brighter colour, and fine y 

 serrated on the margin ; but in some few species they are entire, with small specks ^ 

 the margin, indicatmg the abortive teeth. The inflorescence is racemose or panic ar. 

 axillary or terminal : the flowers, often of large size, sometimes mediocre in dimensions, 



a 



mgle 



luded 



on 



' Mart. Mor. Bras. I c. p. 479. » Loc. eit. tab. 60, in the lower Hn 



* Observations on Fruits and Seeds (edit. Lindley), pp. 62 & 72. * Hem. Mus. xiii. 



•f figures 



