MR. J. MIERS ON THE FAMILY OF TRIURIACEJE. 53 
. geneous, which would not accord with its nature; but if these denote only different con- 
ditions of the embryonary form, the one may be considered as a protoblastous, the other 
as a cotyledonous embryo. On surveying other peculiar embryonal forms, some will be 
better understood by this view of the subject ; for instance, we may conceive that the pro- 
toblastus, instead of forming one compact mass of spherules, as in Balanophoree, Triu- 
riaceæ, &e., may be somewhat less aggregated, so as to assume the shape of elongated 
bundles of cells, such as have been termed paraphysiform : such a form is actually met 
with in Ceratophyllum, where the exterior series of unequal size have been assumed to be 
an unusual number of cotyledons, and the very numerous inner series have been held to 
be a highly developed plumule, while the common. point of their union is considered 
as the radicle. The development of this embryo has been well analysed by Schleiden, 
in his memoir on Ceratophyllum *. Professor Lindley remarks t, that “in this instance, 
as in Nelumbiacee, the highly developed plumule may be a compensation for the want 
of albumen, enabling the embryo to germinate without assistance, as soon as it is ex- 
posed to the fitting conditions.” The leaves of Ceratophyllum appear destitute of all 
nervures, consist of confervoid parallel cells, and dichotomously divide themselves into 
simply articulated hair-like segments, thus denoting a lower order of development than 
has been assigned to it. Independently of this cellular texture, we must bear in mind 
that this genus possesses moncecious flowers, with a simple perianth, having a valvate 
æstivation, almost sessile stamens, an unilocular carpel with a solitary ovule ; and if, 
in addition to these characters, we regard the construction of its embryo, in the view 
above contemplated, its position in the system would rank near Flwiales, as was long 
ago suggested by Bernard and Antoine de Jussieu, followed by Jaume St. Hilaire and 
Agardh, and therefore, as will be seen, not far from Triwriacee. Conterminous with the 
Fluviales we find another family, the Aroidee, which offers many circumstances bearing 
upon this subject. Blume describes Amorphophallust as possessing an exalbuminous 
simple nucleus, homogeneous in texture, with one of its extremities pullulating at one, 
two, or three points, and throwing out fleshy lobes, which overlap each other. The same 
botanist records, that in Aglaonema the seed has a solid nucleus, which, in germination, 
throws out several squamulæ at one end $; and Schott states that the nucleus of Crypto- 
coryne emits several gemmulæ in a similar manner|. This fact has been confirmed 
and illustrated in an admirable manner by Mr. Griffith, in a very interesting 
memoir upon Ambrosinia (Cryptocoryne) ciliata], where he has shown, that at an early 
period the ovule presents an embryo, which then appears to be quite homogeneous, and 
“ entirely cellular,” and that its development is first marked by the production, upon a 
= Linnea, vol. ii. p. 512. f Vegetable Kingdom, p.263. — 
f In Rumphia, i. 138: “in quo ad extremitatem inferiorem umbilicum spectantem und -— 2 ve 3 minute gem- 
mule germinantes observantur; gemmulæ ejusmodi constant squamulis aliquot carnosis sibi oppositis et sese amplec- 
tentibus." (Kunth. Enum. iii. 32.) é age “M 
$ “Embryo semini conformis, exalbuminosus, solidus, ad extremitatem radicularem squam quot munitus. 
—Rumph. i. 130. (In Endl. Gen. Pl. Suppl. p. 1370.) | i 
|| * Embryo cotyledonibus (protophyllis ?) plurimis." —Schott, Meletem. Bot. (In Kunth. Enum. iii. 12; et Trans. 
Linn. Soc. vol. xx. p. 266.) 
{| Trans. Linn. Soc. vol. xx. p- 263. 
