THE LEAF.SHEATH FLAGELLA. 15 
When a Calamus is not decidedly scandent, but is a derivate of species which 
climb and therefore possess weli-formed flagella, we find that rudimentary flagella 
are present. 
Flagella are quite absent from species with an erect stem, such as €. erectus; 
C. arborescens, etc. In the flagelliform species flagella are also usually absent in the 
earlier stages of the plant and only make their appearance when the plant has 
reached a certain height and begins to produce spadices. In many species, however, 
it is found that spadices alternate with flagella. 
In those species where the leaves are cirriferous and the spadices are short and 
panicled, we observe now and then a rudimentary flagellum; in O. latifolius, for | 
example, I have had occasion to note the presence of rudimentary flagella, 8-10 
em. in length, filiform, sheathed by quite tubular prickly spathes, while in other 
cases the place usually occupied by a spadix is indicated by a small protuberance. 
Such rudimentary flagella have remained abortive because it was not natural for the 
spadix which they represent morphologically to become flagelliform. 
Very probably in the non-flagelliferous Calami the young plants may bear such 
abortive flagella; this I have had an opportunity of noting in ©. erioacanthus. 
Whether a species be flagelliferous or not may be ascertained from herba- 
rium specimens even if the flagella are actually missing, because if the spadix is 
elongated and ends in a weil-developed clawed flagelliform appendix, some of the 
leafsheaths are almost certainly flagelliferous; on the other hand, if the spadices 
be short, compact, panicled and not flagelliferous, most probably the sheaths are 
not flagelliferous and the leaves of the higher part of the plant are cirriferous. 
VII.—The Ocrea. 
The ocrea of Calam is a tubular stipule, occasionally split into two parts, 
bordering the mouth of the leaf-sheaths. In many cases the ocrea is much elong- 
ated and conspicuous, membranous or chartaceous in texture, glabrous or more or 
less clothed with hispid hairs or spicules, sometimes even more or less spinous; not 
infrequently it is very short or is reduced to a short ligule in the axil of the 
petiole. 
Sometimes the ocrea is persistent and clothes the base of the sheath immediate- 
ly above its own; its chief function seems to be the protection of the younger 
parts of the terminal shoot. Most frequently after the expansion of the leaves the 
ocrea decays and is lacerated or reduced to fragments or filaments, scarcely 
retaining any trace of its shape ; ; Sometimes, being deciduous or of a transitory 
nature, its former presence is revealed only by a narrow scarious rim at the 
mouth of the sheath. 
In the African Calami the ocrea is usually rather elongate and tightly clothes 
the base of the sheath above its own, but its outer side is more elongated or 
produced than that facing the petiole; in these species, therefore, the ocrea assumes 
Deed; din i of the mouth of a beaked id and we Pid term it E 
liguliform." . | 
-A 
