MR. J. MIERS ON THE BARRINGTONIACE X. 53 
which bears much analogy to the nipple-shaped process described by me in Clusia, арра- 
rently divisible into 2 or 4 lobes, which formerly I regarded as rudimentary cotyledons’. 
The kind of solid embryo found in Butonica and many other genera, under different 
modifications, consists, as before said, of an external exorhiza and an internal neorhiza, 
the latter having a plumule at one extremity and a radieular nipple at the other, the 
ends expanding in opposite directions in germination, the one being the precursor of the 
ascending stem, the other of the descending root ; between the two main fleshy bodies, 
and adhering to both, is the medullary sheath’, consisting of elementary vascular tissue, 
which, by the nutriment afforded on either side, yields woody fibres to the root, and gives 
origin to the wood, bark, and leaves of the new plant, the neorhiza, void of vessels, 
remaining as the central pith, while the exorhiza, also without vessels, merely gives out 
all its substance as nutriment to the general growth, and, without expansion, gradually 
dies away, thus performing simply the function of a cotyledon. То avoid frequent repe- 
titions in the following descriptions, this kind of embryo will be said to be mesopodal, 
because the expansion of its growth in germination is always in the axial portion (neo- 
rhiza), while the outer portion (exorhiza) finally becomes atrophied. 
The name tigellwm has been given to the analogous kind of embryo in Xanthochymus* 
and other Guttifere ; but it appears to me a very objectionable term, because the word 
tigella, invented by Mirbel in 1815*, and since used by all French botanists, denotes 
that portion of the plumule, in ordinary cases, which lies between it and the neck of the 
radicle: this, however, is seldom visible till after the commencement of germination. 
Jussieu also used it in the same sense?; but in a previous page he applies it to the 
great fleshy mass in the embryo of Pekea^. Consequently the name /ige//wn ought not 
to be given to an entire embryo of peculiar form when the same designation has been 
extensively used by botanists to denote a very small portion, and that often invisible, in 
the ordinary forms of the embryo in the seeds of both exogenous and endogenous plants. 
Such are the leading characters of the Barringtoniacee, from which it will be seen 
that they differ widely in their structure from the Муг/асев, and equally so from the 
Lecythidacee. With the former they have hardly a single character in common ; for the 
apparent similarity of their numerous long stamens is destroyed by the insertion of each 
filament separately upon а perigynous disk, while in the Barringtoniacee they stand in 
many dense series, all united at their base into a monadelphous tube, inserted on the 
outer margin of a distinctly epigynous disk. From the Lecythidacee they differ in a 
totally distinct floral structure. 
The Barringtoniacee appear to me to approach nearer to the Rhizophoracee; indeed, 
if we imagine in any plant of the former a flower with the staminiferous tube aggluti- 
tinated to the limb of the calyx, it would at once be referred to the latter family ; it 
would be especially close to the new genus На’тепа, established by me upon а plant 
! Linn. Trans. xxi. 246, tab. 26. figs. 8-10, 26, 27. 
* Mirbel, Elém. i. 110; Juss. Cours Elém. p. 48, fig. 88, 99. 
3. Ann. Sc. Nat. sér. 4, vol. xiv. tab. 17. fig. 15; Trimen, Journ. Bot. 2nd ser. vol. iv. р. 67, tab. 160. 
* Elém. pp. 50, 601, pl. 57. 
* Cours Elém. p. 365. fig. 446, p. 366. fig. 447. 
* Loc. cit. p. 350. fig. 420 (in adnot.). 
SECOND SERIES.—BOTANY, VOL. I. I 
