I K T E O D U O T O E Y ESSAY.
SoQietimea the spines arc confluent and, by their united bases, form membranous
crests which are crowned by permanent or deciduous needle-like spiculae.
Not infrequently the spines, especially when rather strong, leave on the surface
of the sheaths or even on the underside of the leaf-rachis, a more or less distinct
and deep impression of their outline; this is due to the fact that when the leaves
are closely packed in tho terminal shoot the spines are turned upwards, and are
pressed against the surface of the organ from which they originate, while, after the
expansion of the loaves, these spines become at first spreading and at length horizontal
or deflexed.
Whenever the rachis is prolonged beyond the ultimate leaflets as a filiform or
whip-like appendix, or when a similar appendage crowns the summit of the spadix,
or when leaf-sheath flagella are present, the armatm-e of these parts consists of
hooked prickles or claws, while at the same time the lower surface of the leaf-rachis
and the attenuated portions of the spadices interposed between two partial inflorescences
are usually similarly armed.
The claws at times are slender but more frequently they are robust, with
a broad and swollen base and a very sharp and short curved point. In the first or
lower portion of the rachis they are usually solitary, but they became 2-3-nate and
even digitately 5-nate upwards when the rachis is prolonged into a cirrus; in this
case the claws usually form i-whorls at regular intervals. In very robust species
they even form |-whorls, the claws being then 6-7 in number and confluent by
their bases. It is, however, very rare, except at the extreme apex, for the circle
of claws to be closed and form a complete whorl. The leaf-sheath flagella and
prolongations of the spadices, when present, are similarly armed.
The different kinds of spines of Calamus are all, as already stated, outgrowths
of the peripheral tissues and consist of their lengthened cells with tapering ends
{dostreg), which are very closely united and form externally a verj' resistent sheath
of prosenchyma, while the interior is composed of a more or less abundant wall-like
or muriform parenchyma. In the spines of C. Flagellum YAE. Jsarinensis I have
happened to find besides a few slender bundles of spiral vessels.
Every kind of spinosity, but in an especial manner that of Calamus, is assumed
by me to owe its origin to certain stimulative causes acting on tissues liable to
hypertrophic cellular growth. I suppose therefore that a bite, a sting, even simple
contact, or any other agency capable of irritating tho 'protoplasm, when in the
full force of its vitality, may have produced, during the plasmatical era—that is to
say, in the very early periods of the evolution of organisms, and under special
circumstances—certain local hypertrophic excrescences. These, having in the course of
time acquired the power of being transmitted to the progeny, may have been
changed into spines.
I n the category of spines, rather than in that of rudimentary leaf-blados, I
would also include the scales of the loricated fruits of the Lepidocaryece.
III.—The Stem,
The stem of Calamus is usually slender and very long; for as Calami are Palms
of very rapid growth, the annular thickenings or rings of the stem where the leaves
are attached are very far apart and consequently the internods are very long and
sheathed by the basal tubular part of the leaves.
In a very few species the stem is erect; in this case it never attains a great
height. In C. arhorescens, which is I believe the largest known erect species, the
stem reaches a height of 5-6 metres, and, when divested of its leaves, a diameter
of, at most, 6 cm. The stem of C. hacularis, another non-climbing species, is
about the size of a common walking cane.
The species of Calamus, which possess erect stems, appear to be of less rapid
growth than the climbing ones, as their joints are rather short. I know only one
species which is almost stemless; this is C. pi/fjmaeus the small Bornean Palm
abeady alluded to, certainly the most diminutive species of the whole genus,
C. Lohhianus appears also to be an almost stemless plant. C. tonJcinensis and C.
salicifolius are bushy species with rather short slender recumbent stems. C. acanthospathtis
appears to be at first erect, but ultimately snbscandent, never however attaining
a great length. The stem, in climbing species, with the shcathB on. varies from
4-5 mm. in diameter in some varieties of C. javunsk and in C. filiformis, to 10 cm.
in C. andamanicus; when divested of the sheaths, the range is from 2-3 mm. up to
4 cm. The length of the internodes is usually great and attains the extraordinary
length of 90 cm. in C. Scipionum,
The total length of the stems of Calami has been gi-eatly exaggerated. Roxburgh
(Flora Indica, Vol. I l l , page 777) assigns to his C. eztensus a length of from two
to three hundred yards, but I think that even if feet instead of yards be meant,
this length is still excessive. Loureiro, too, gives to his C. rudentum the extremely
unlikely length of 500 feet. With regai'd to this subject I have to say that I
never measured a Calamus at all approaching these dimensions, and that all those
observed by me were certainly under 50 metres (about 150 feet). As Calami
are climbing plants, the entire length of their stems may be approximately
estimated by the height of the trees which support them; often, however, the lower
part of their stems is procumbent creeping long distances on the soil of the forest, so
that a Calamus plaut may be considerably longer than the height of the tree from
which it is suspended. This is brought about by the fact that the leafy crown of
a palm of this kind is, on account of its being too slender, unable to miiintain itself
freely above the aerial plane of the forest and as new leaves and spadices or flagella
are successively produced, those which preceded them and are situated lower down
the stem gradually decay or lose their hold and do not succeed in retaining the
plant in position by their hooked spines. Thus it happens that while the top of the
palm strives to rise above and even to spread its fronds over the crowns of the
loftiest trees, it has on account of its weight a contrary tendency to find a lower
level. As the result of these two opposing agencies, the crown of the plant remains
constantly at about the same atrial level, while the lower portion of the naked stem
creeps for a considerable distance on the ground below.
The internodes of the stems of the Calami are sometimes exactly cylindric,
but not infrequently are slightly enlarged upwards; those of the higher
or adult part of the plant usually have a slightly raised longitudinal ewelliiig or