32 INTRODUCTORY ESSAY. 
for those found in the fold of the blade of the leaflets at their base in the lower 
surface may be quoted O, aruensis and C. Hoilrungit. | 
Usually we observe axillary nectariform callosities on the spadices when the 
partial inflorescences are situated outside the mouth of their respective spathes; 
and most commonly, where the) larger branches of the spadix are provided with 
an axillary callus, these appear also at the successive divisions and even at the 
insertions of the spikelets and of the involucrophora. 
The -essential requisite for a nectarial structure is the secretion of sweet fluids; 
therefore in Calamus, the transverse rima of the callus, if this be really a nectary, 
ought to be the opening for the exudation of such fluids; but in the herbarium 
Specimens examined by me, I have never been able to discover the slightest sign of 
their presence, nor have I seen any indication of their having been. resorted. to by 
insects of any kind, in search of nectar. 
It is only from observations on living plants that wel may acquire any definite 
knowledge of the nature of the nectariform surfaces of Calamus. 
X X,-- Calami under Cultivation, 
Although the species of Calamus, the cultivation of which bas been attempted in 
the hot-houses of extra-tropical countries are pretty numerous, the number of those 
which have become permanently established is small, owing to its being very difficult to 
provide them with conditions of existence like those enjoyed in their native countries, 
The Calami in our hot-houses therefore give but a faint and poor idea of the elegance 
of their foliage as it appears at the summit of a long slender and climbing stem. 
Young plants of Calami are, however, considerably appreciated by. horticulturists on 
account of their highly ornamental, bright green, graceful pinnate leaves, so that they 
are frequently offered for sale in commercial catalogues of living plants, 
But the names by which cultivated Calami are known to horticulturists are, with 
hardly an exception, incorrect; and since, on the other hand, horticulturists are in the 
habit of putting on the market small seedlings or very young non-characterized plants, 
the foliage of which usually exhibits much uniformity in the various species and always 
differs considerably from that of the adult plant, it becomes very difficult for a botanist 
to reduce the species rashly proposed by horticulturists as new to their’ true position 
in scientific nomenclature. | : 
I have been able, from specimens of leaves of cultivated plants preserved in the 
Herbaria at Kew and Berlin, to establish the fact that many of the supposed Calami 
are species of Daemonorops, for it appears that some species of this genus are more 
| easily cultivated than most species of Calamus, but I have very seldom been able from 
specimens of this kind to determine the actual species to which they belong, 
In Very many cases the exact naming of these horticultural Calami has been rendered 
kae e owing to the fact that their appearance in European hot-houses has 
n qute ephemeral, and that many with newl sed names have disappeared 
for ever from cultivation, : S £t : 
In the French edition of Nicholson and Motetts Dictionnaire d’ Horticulture ZT 
cultivated species of Calamus are enumerated and many of them bear the names of 
