56 MR. J. MIERS ON THE FAMILY OF TRIURIACEÆ. 
the plants of this family differ wholly from the Triuriacee, in having distinct, entire, 
large leaves, with long amplexicaul petioles, and intrapetiolar vaginant stipules, in their 
female flowers arising from the superior axils, in the frequent absence of any perianthium, 
ovules often suspended from the ventral suture, and very delicate membranaceous testa. 
Their exalbuminous macropodous embryo may be considered as an approximation to the 
structure of the nucleus of Sciaphila. 
With the Juncaginee they agree in their inconspicuous spicate flowers, numerous 
carpels, with a solitary erect ovule and exalbuminous seeds; but these again differ in their 
large leaves, with parallel nervures, 2-serial floral envelope, extrorse stamens upon long 
filaments, and sometimes two ovules in each carpel. The Juncaginee, however, have been 
considered by some as a suborder of the Alismacee, by others to be more nearly allied to 
Fluviales and Aroidee, on account of their spicate flowers: indeed, though placed at so 
great a distance in the system by Endlicher, they are really so closely allied, that the 
genera Ruppia and Potamogeton are placed by some botanists in Fluviales and by others 
in Juncaginee. 
If we agree in placing these four families in closer juxtaposition in the system*, the 
Triuriacee will find a place near them; but, upon the whole, the greatest amount of 
approximative characters will be seen to lean towards the Flwviales, especially through 
Potamogeton (which genus is arranged by Mr. Brown among the Alismacee), and which 
possesses a simple perianth of four segments in a single series, with valvate æstivation, 
and four stamens opposite to them, globose simple pollen and uniovular carpels; and 
although it bears hermaphrodite flowers, it must be remembered that Sciaphila is some- 
times bisexual. Najas and Caulinia, as before observed, present also carpels with a soli- 
tary erect ovule. . 
It now only remains to define the characters of this small order. 
TRIURIACEA, Miers (1841). Triuraceæ, Gardn. (1843). Triuridacee, Lindl. (1846). 
Herbe parvulæ, subhyalinæ ; rhizomate fibroso, interdüm substolonifero ; caule subsimplici, texturä cellu- 
losä, vasis deferentibus in axi centralibus ; foliis alternis, bracteiformibus, sessilibus, nervis destitutis. 
Flores monoici, vel dioici, rariüs polygami, spicati; pedicellis alternis, 1-floris, basi bracteatis. 
Perianthium in utroque sexu simile, 3-4-6-8-partitum, hyalinum, texturá celluloso-bullatä, vel 
papilloso-rugosa ; laciniis ovatis, acutis, basi in tubum brevissimum coalitis, apice interdüm processu 
elongato donatis, æstivatione valvatis. Stamina numero varia, pauca, in fundo perianthii fere sessilia, 
supra androphorum sæpissimè magnum carnosum inserta; anthere 4-loculares, 2-valves, rariüs in 
lobos 2 sejunctæ, Ovaria plurima, in gynæcium toro adnatum densissimè aggregata, 1-locularia ; 
ovulo unico, e basi erecto. Stylus excentricus, introrsüm lateralis, sæpissimè ferè basilaris, glaber 
aut plumoso-fimbriatus, Stigma obsoletum, vel truncato-clavatum. Carpidia plurima, baccata, 
radiatim excentrica, obovata, stylo persistente ferè basilari notata, coriacea et indehiscentia, vel 
interdùm utricularia dorso valvatim dehiscentia; caryopside obovata, tela arillæformi donatá: testd 
* This . 
Lee pim: — in the : Prodromus Flore Nove Hollandiæ” of Mr. Robert Brown, where the Aroideæ, 
» Alismacee, and Juncaginee are placed in contiguity, with the intervention of Pandanus alone, of which it 
is worthy of remark that it also offers the iarity of i i 
à de a Du Did er an entire and simple embryo: and nearly the same arrange- 
