OF CEYLON AND INDIA. 
359 
of a leaf. Whether this development has any functional 
object like that of the palisade layer must be left for future 
determination ; it seems a little improbable in view of the 
fact that the younger parts of the thallns, which probably 
do most of the assimilatory work, are without it. As the 
development proceeds, the thin marginal parts of the thallns 
commonly shrivel up, and often fall away altogether, leaving 
only the stout rib, so that a piece of the base of the thallns 
of this form is indistinguishable from that of var. 
laciniata, though the early stages of the two are so utterly 
different. 
The .secondary shoots in the vegetative condition are just 
like those of the other Dicræas (PI. XXII., fig. 3). Ulti- 
mately the lower ones, usually for about a quarter of the 
length of the thalius, but sometimes more, become floriferous 
in the usual way by growing out from the thalius, enlarging 
the sheaths of a few leaves and losing their tips, thus giving 
rise to broadly helmet-shaped bracts. The spathe is en- 
closed in the upper bracts till a later period than in D. 
elongata, and frequently the bracts do not even separate till 
the air touches them. Although the vegetative shoots are 
erect, the flowering ones usually lie more or less prostrate 
until the curving upwards of the spathe is accompanied by 
more or less curvature of the bracts. The spathe is broadly 
funnel-shaped (PL XXIV., fig. 1). The flower is of the usual 
Dicræa type, on a short stalk, with short stigmas and stamens. 
It is wind-fertilized and usually autogamous, and practically 
all flowers appear to set seed. This form at Hakinda, how- 
ever, lives so deeply submerged that it does not always set 
very many flowers. The fruit stands on a pedicel about 6 
mm, long which becomes thin and elastic in the usual way by 
dropping its cortical tissues. 
Rejuvenescence .— species exhibits very extensive pro- 
duction of new growdng points in case of any injury to the 
thallns, such as the breaking off of a portion of it, or injury 
to the tip caused by exposure to air. New growing points 
