2 INTRODUCTORY ESSAY. 
According to the view now explained we can imagine that the hooked spines owe 
their origin to a special sensibility of the protoplasm, which at certain determinate 
points, where the reaction to the stimuli happened to be more effective, induced 
the tendency to stretch towards and twine round extraneous and heterogeneous 
bodies. The causes which have given origin to the hooked spines ought apparently to 
belong to the class of causes which have produced the numerous other contrivances 
whereby an erect plant acquires the power to climb. This statement is, to a certain 
extent, borne out by the fact that all Palms which have hooked spines on the leaf- 
rachis and on the spadices, or which have clawed cirri at the ends of the leaves, 
or have the leaf-sheath flagella similarly armed, are climbing species; whereas, when 
a Palm is only armed with straight spines it is certainly an erect one, or is 
bushy and short-stemmed, like Mauritia, Eugeissonia, Sagus, Zalacca, | Oncosperma, etc. 
All scandent Calami, or to speak more generally, all climbing Asiatic Palms owe 
their fitness for this kind of existence to the transformation into “claws” of the 
short straight spines which defend certain parts of the plant; whereas species of 
the American genus Desmoneus and of the African genera. LEremospatha and 
Ancistrophyllum, which also climb, are indebted for this property to the transforma- 
tion into rigid and valid hooks of the smaller and apical leaflets of their fronds.* 
Among the -numerous species of Calamus known to me, only one, the small 
almost stemless C. pygmaeus, found on the tops of the mountains of Borneo, is able 
to raise itself a few feet from the ground through the surrounding. shrubs by means 
of the small deflexed branchlets of its filiform^spadices, which act as hooks. 
As all Calami have, without doubt, originated in the densest tropical forests, and 
as the power of attaining the summits of the trees among which they have to 
struggle for.air and light has been one of their most important needs, contrivances 
of various kinds and different nature have been evolved for the accomplishment of 
this purpose; consequently, the numerous modifications induced by this circumstance 
in their organs, supply most important characters whereby it is possible to 
distinguish the various species of the genus Calamus, 
The spinosity, together with slight morphological modifications in certain organs, 
is the principal contrivance by which Calami climb. These modifications are:— 
(1) the extension of the summit of the leaf-rachis into a cirrus: 
(2) the extension of the main-axis of the appendix into a long filiform-clawed 
appendix : 
(3) the transformation of the spadices into long whip-like clawed Organs, 
With the help of these characters it is nof diffieult to bring the greater part of 
the species of Calamus together into more or less natural groups. 
The spathes also afford important characters that can be made use of in 
classifying the species of Calamus, though to a less degree than in the case of 
Daemonorops, a genus in which the chief funetion of the spathes is to protect the 
flowers whereas in (Calamus the Spathes also often to a certain extent assist the 
plant to climb, oo 
© Owing to. the seoulies anda ce 
S "Owing to the peculiar arrangement which prevails in the Botanical Museum of Florence, where the library 
ds been placed some kilometres away from the herbarium, I have not of late had any opportunity of consulting 
e paper, by F. O. Bower, on the modes of climbing in the genus Calamus (Annals of Botany, vol. I, p. 126). 
