this respect and in the more important character of the position of the Embryo Junceæ differ also from Restiaceæ, to which they more nearly approach in habit.
Three very remarkable genera, which I have referred to Junceæ, are peculiar to Terra Australia. Of two of these Calectasia and Dasypogon, each consisting of only one species, figures and descriptions are annexed to this essay.
Of the third, Xerotes, 24 species have already been observed. This genus is somewhat more abundant in the principal parallel than in other parts; but it is very generally extended, and is more frequent within the tropic than in Van Diemen's Island. Xerotes, in the structure and appearance of its flowers and in the texture of Albumen, has a considerable resemblance to Palms, but it wants the peculiar characters of the seed and also the habit of that remarkable order.
Flagellaria, which I have added to Junceæ, differs from Xerotes chiefly in its pericarpium, and in the form and relation of its Embryo to the Albumen, which is also of a different texture; in all these respects it approaches to Cyperaceæ, with some of whose genera it has even a certain resemblance in habit. This genus has usually been found only within the tropics, but in New Holland it extends as far as 33° S. lat.
Philydrum, which I have annexed to Junceæ, has always appeared to me an insulated genus, yet though not referable to any established natural order, it may be compared with several in certain respects. In the structure of its stamina it may in one point of view be said to be intermediate between Scitamineæ and Orchideæ; in that of its pericarpium and even of its seeds it has some affinity to the latter order; yet it differs from both of them in almost every other respect. In general appearance, it bears a considerable resemblance to Cartonema, which belongs to Commelineæ. In some parts of its structure it may be compared with Xyris, and perhaps with Burmannia; a genus which I have likewise annexed to Junceæ, but whose real affinities are equally obscure.
Philydrum pygmæum differs in so many respects from P. lanuginosum that it may probably hereafter be considered a distinct genus; and a very few additions to this tribe of plants would sanction their formation into a separate natural order.
