J81 
Alliance HI. CASUARALES. 
Essential Character. — Carpels solitary . Sterns jointed and furnished with sheaths. , 
This singular character designates the Casuaracese at first sight, and shews 
an approach at this part of the system to Equisetaceie among Gymnosperms. 
Order CXXX. CASUARACE.E. 
CasuarinejE, Mirb. in Ann. Mus. 16. 451. (1810) ; R. Brown in Flinders, 2. 571. (1814). 
Essential Character. — Floivers unisexual. Males : Flowers whorled about the 
articulations of the jointed rachis. Bracts 2, membranous, right and left of a two-leaved 
calyx, the sepals of which stand fore and aft, and adhere at their points, and at the time of 
flowering are separated from their bases and carried up by the stamen in the form of a 
calyptra to the anther. Stamen 1 ; filament subulate ; anther erect, two-celled, with parallel 
contiguous cells opening by a longitudinal fissure. Females, in very dense spikes. 
Rachis not jointed. Flowers numerous, solitary in the axils of imbricated bracts. Calyx 0. 
Ovary lenticular, with a solitary ovule. Styles 2, united at base. Caryopsides winged, 
hidden in thickened bracts, sessile. Seed erect, without albumen. Embryo inverted. — 
Branching weeping trees, with jointed shoots, the internodes of which are striated. Leaves 0 ; 
in their room short, toothed, ribbed sheaths. Flowers in spikes. Chiefiy from Bartling. 
Affinities. Brown, in the Appendix to Flinders’s Voyage, has the fol- 
lowing observations on the structure of this remarkable genus. 
“ In the male flowers of all the species of Casuarina, I find an envelope of 
four valves, as Labillardiere has already observed in one species, which he has 
therefore named C. quadrivalvis. Plant. Nov. Holl. 2. p. 67. t. 218. But as 
the two lateral valves of this envelope cover the others in the unexpanded 
state, and appear to belong to a distinct series, I am inclined to consider them 
as bractese. On this supposition, which, however, I do not advance with much 
confidence, the perianthium would consist merely of the anterior and posterior 
valves; and these, firmly cohering at their apices, are carried up by the 
anthera, as soon as the filament begins to be produced, while the lateral valves 
or bractese are persistent ; it follows from it, also, that there is no visible peri- 
anthium in the female flower; and the remarkable economy of its lateral 
bractese may, perhaps, be considered as not only afibrding an additional argu- 
ment in support of the view now taken of the nature of the parts, but also as 
in some degree again approximating Casuarina to Coniferse, with which it was 
formerly associated. The outer coat of the seed or caryopsis of Casuarina 
consists of a very fine membrane, of which the terminal wing is entirely com- 
posed ; between this membrane and the crustaceous integument of the seed, 
there exists a stratum of spiral vessels, which Labillardiere, not having dis - 
tinctly seen, has described as an ‘ integumentum arachnoideum ;’ and within 
the crustaceous integument there is a thin proper membrane, closely applied 
to the embryo, which the same author has entirely overlooked. The existence 
of spiral vessels, particularly in such quantity, and, as far as can be determined 
in the dried specimens, unaccompanied by other vessels, is a structure at least 
very unusual in the integuments of a seed or caryopsis, in which they are very 
seldom at all visible ; and have never, I believe, been observed in such 
abundance as in this genus, in all whose species they are equally obvious.” 
Blume remarks that Casuarina is undoubtedly related to Myrica in its 
ovaries, its single erect ovule, and its exalbuminous inverted embryo ; but it 
dificrs so much in its habit, that it is better, with Mirbel, to consider it a dis- 
tinct family, which dificrs from Myricaceee, in its fructification, especially in its 
achenia with membranous wings included between two lateral scales, which. 
