24 INTRODUCTORY ESSAY. 
originated (Prate II, fig. la) The essential part of the involucrophore is a small 
calyx, cup, cuplet or disk which corresponds to a spathel and is most usually sessile; 
in several species, however, it is more or less narrowed to the base, as in C. 
Grifithtanus and C. Zollingerü (Puare II, figs. 6-8a) or is even distinctly pedicellate, 
The latter condition is very evident in C. symphysipus, C. heteracanthus and allied 
species, in C. evilis and allied species, and in C. unifarius var. Pentong (PrarE II, fig. 
la) The pedicel of the involucrophore in the species mentioned clearly demonstrate 
the axial origin of the involucrophore. 
The involuerophore is never absent from the female spikelets and presents 
important diagnostic characters in its shape, and in its mode of insertion, whether sessile- 
or pedicelléd, included in or exserted from its own spathel, free from or partially 
adnate to the spathel above its own. As the involucrophore represents a contracted 
branchlet, or the axis of a rudimentary spikelet, emerging from the axilof its spathel, 
it reproduces the peculiarities inherent in all the other divisions of the spadix and 
just as at the insertion of the spikelets there is a specialized swelling or callus, which 
I have supposed to be nectariferous, we find this same callus with its transverse cleft 
or rima repeated in the axil of the involucrophore (Pare II, fig. 1i). 
Within the involucrophore and usually moulded on this is the proper involucre of 
the flower which corresponds exactly with the involucre of the male spikelets. Had 
we made use of the term spathellule for the second appendicular organ of the male 
spikelets, we ought to have used this term also for the involucre of the female 
spikelets and not for the involucrophore, a usage that must have led to confusion. ° 
The involucre in female spikelets is usually concave and cupular’so as to admit 
of the reception of the base of its flower; its margin is truncate and usually entire, 
but on the outer side it is more or less distinctly marked by two small teeth, between 
which the margin is more or less deeply lunately excised. Sometimes the involuere 
is almost explanate and discoid or even appears as if made up of two bracts, which 
in a few instances are almost separate, the apices of these bracts corresponding with 
the teeth of the involucre when it is cupular, On the involucre of the female flower 
externally, on a peculiarly shaped surface corresponding in position to the  lunate 
excavation of the margin, is invariably inserted a neuter flower (Prats I, figs, 8, 10, 
11e). | 
The small usually sharply defined surface on which the neuter flower is 
inserted I have termed the “areola” of the neuter flower. This areola is most 
usually lunately shaped, somewhat depressed or developed more in breadth than in 
height, with the horns corresponding to the two marginal teeth, Sometimes, however,. 
it is more developed vertically than horizontally and assumes a more or less ovate 
or lanceolate shape as in (€. Griffithianus (PLATE II, fig. 8c),.or is more or less 
concave or subinvolucriform, as in C. deerratus. The areola is not, however, always 
sharply defined; in some cases it is depressed or linear, or its place is simply 
marked by a small callosity (Prate II, fig. le) or by a punctiform scar, Sometimes. 
too its place is taken by a very short pedicel which supports the neuter flower, as 
in C. adspersus and C. Henryanus; this pedicel evidently represents there a second 
joint of the small and contracted  spikelet from which the fertile and the 
abortive flowers spring. In C. Cumingianus and €, nitidus the neuter flower has at its 
