ылады EET РЕТ GEENE EEEE 
MODE OF GROWTH OF ZALLIA CALLITRICHA. 227 
I leave the thoroughly distinct forms of В. Robertiana (Harvey) and В. Mariana 
(Harvey) out of view, not having investigated them with sufficient pains to be able to 
contrast them in their relative bearing to the points presented by Mr. Moseley's plant; 
but confining our attention to those forms combined under the designation В. calli- 
tricha, we see they are all of beautifully more or less well-developed plumose habit, very 
unlike Mr. Moseley's form. It would, however, be trenching on rather unsafe ground 
for me to venture to distinguish this plant as a new species. 
In B. catlitricha and the forms conjoined with it under that designation, the whole that 
has been said in relation to Mr. Moseley's form, as regards the pits and stoppers, the 
ramifieation-cells and mode of evolution of the branches and cortex, in a general way 
applies. The differences in the different forms lie in the various figures of the different 
constituent cells forming the build-up of the plants, until we come to the ultimate 
ріппге with their pinnules. Unlike Mr. Moseley's plant, where these ultimate pinnules 
are rarely and only fitfully given off, in the В. callitricha forms they are methodically 
and pretty uniformly given off from the cells of the ultimate little rachis—always by 
interposition of a ramification-cell of the first degree only, and so as to produce à plume 
of ovoid or lanceolate or hastate outline, according to the ** species." 
It becomes worthy of remark that whatever the outline of these plumes, and conse- 
quent effect or habit of the plant in its entirety, the lowest outer component thereof, 
looking like a pinnule of the same nature and origin as the rest, is not really so, but is 
in fact the homologue of the lateral “ stipule-like” secondary branch described in Mr. 
Moseley's plant :—there mostly, or at least often, solitary ; here, along with the close array 
of pinnules, contributing to make up the ** plume," and rendering itself quite conform- 
able with the true pinnules. That is to say, it is a true secondary branch, being ап 
emanation from the ramification-cell of the second degree belonging to the older rachis 
from which that bearing the pinnze starts, as this latter is an emanation from the preceding 
ramifieation-cell of the first degree; and from the ultimate minor rachis standing 
thereon, in turn there emanate all the pinnules standing above this secondary branch, 
which is conformable with the piunules, and forms part and parcel of the ** plume." 
It sometimes, indeed, happens that this lower branch grows inordinately in length, 
refusing to comport itself like the line of pinnules above it; I did not, however, ever 
notice a case in which it branched or gave off secondary pinnules or “ pinnelle.” In 
Mr. Eaton’s form, sent by Prof. Dyer, the inordinate growth of this accessory branch 
seemed more common. 
The ultimate terminal or apical **plume" of each ultimate rachis in the typical 
B. callitricha must, however, be excepted; for its pinnz аге wholly made up of short 
stout tapering branchlets, each standing on a ramification-cell, all of the first degree, а 
` continuation of the penultimate rachis being its rachis. In other words, these do not go 
on to become ultimate rachises themselves, do not produce ramification-cells, hence no 
“pinnelle ;" but together they form an apical “ plume," of more or less lozenge-shaped 
general outline; and sometimes the upper cells remain inactive, produce no ramification- 
cells, and do not ramify. Sometimes, indeed, one or two of these apical pinne 
(branchlets) may make an attempt from a few of their cells to give off ultimate pinnelle, 
