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BOTANY OF TERRA AUSTRALIS.
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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 as a distinct genus; and a very few additions to this tribe of plants would sanction their formation into a separate natural order.


RESTIACEÆ. The principal character distinguish- [579 ing this family from Junceæ and Cyperaceæ consists in its lenticular embryo being placed at the extremity of the seed opposite to the umbilicus; from Junceæ it also differs in the order of suppression of its stamina, which when reduced to three are opposite to the inner laciniæ of the perianthium; and most of its genera are distinguishable from both these orders as well as from Commelineæ by their simple or unilocular antheræ.

With the exception of Eriocaulon, Tonina, and Xyris, the order appears to be confined to the Southern hemisphere. In Terra Australis its maximum is in the principal parallel, but it extends to the southern extremity of Van Diemen's Island, where it is even in considerable