CALAMUS. 
INTRODUCTORY ESSAY. 
1. Biological and General Notes. 
Tue species included in the genus Calamus are usually slender elegant Palms. 
which have, during the evolutionary period, acquired the power of raising their 
leafy crown above the heads of the loftiest trees in primeval tropical forests of the 
Old World. 
We may suppose that originally the species of Calamus were delicate, standing 
Palms endowed with a very active and rapid growth, and of such a structure as to 
render the increase of their stem in length more easy than its increase in diameter. 
This peculiarity, coupled with their tendency to overgrow other plants in search of 
light and of eonditions more suitable for the fertilization of their flowers may have 
been acquired, according to an hypothesis of my own,* during the period—very 
remote in the evolution of organised beings— which I have termed the  plasmatical 
era," by means of the hooked spines with which these palms are furnished, which 
endow them with the faculty of suspending themselves from neighbouring plants and 
even of rising above them. 
A Calamus in order to change its erect habit into a climbing one had, according 
to this hypothesis, necessarily first to acquire the organs needed to ensure this essen- 
tial condition of. its existence. These organs are, with hardly an exception, common 
spines which have assumed a hooked shape. 
The means whereby Palms have been enabled to acquire spines of this kind is 
ee one of those morphological problems which, like the metamorphosis of any other organ 
of living beings, we are unable to explain scientifically, but as to which we are obliged 
to remain satisfied with some more or less plausible hypothesis. 
I suppose therefore that the spinosity of Palms, especially that which besets the 
leaf-sheaths, was originated by the stimulus induced in the very sensitive peripheral 
tissues by animals in search of nutriment in the youngest and most tender parts of 
the plant.T 
I suppose therefore that'the young central parts of every spinous Palm: must 
have been coveted for nourishment by numerous animals, had they not been defended 
by spines. It is quite impossible for me to explain now, even superficially, how the 
stimulus produced by the action of certain animals on the irritable vegetable tissues 
may have given rise (in very remote times) to hereditary epidermal outgrowths or 
hyperplasia; organs of such a nature as we may consider the spines to be. Nor can 
I explain how it is possible that the stimulus which exercised its action at a definite 
point may have induced the production of spinous organs in almost every other part 
of the plant. As we have already seen, the spines which enable the Calami to climb 
are hooked, or are of the kind that, in the descriptions of the species, we have 
agreed to term “claws.” These claws are almost exclusively met with on the axial 
parts of the spadices, on the leaf-sheath flagella (abortive spadices), on the leaf-rachis. 
and, especially, on its prolongation or cirrus. | 
|* Beccari: Nelle Foreste di Borneo, p. 293. 
f Beccari: Nelle Foreste di Borneo, p. 179. 
Axs. Roy, Bor. Garp. CarcurrA Vor. XI. | : 
