In the Herbarium of the voyages, there are a few plants belonging to Rhamnus, Ziziphus, Ceanothus, or Pomaderris, and Celastrus, but both families prove to be comparatively rare in the intratropical parts of Terra Australis, beyond which Cryptandra seems only to exist. Upon the north-western shores, a species of Ziziphus (common to the East and North Coasts) forms a tree of large dimensions, where also an undescribed Celastrus has been discovered. Since Pomaderris evidently increases from the verge of the tropic southerly towards the parallel of Port Jackson, where its maximum exists, and as it is frequent on the South Coast, it is highly probable the West Coast is not wanting of the genus, particularly as traces of it were found on Dirk Hartog's Island.
LEGUMINOSEAE. There are upwards of one hundred and forty species of this extensive natural class in the Herbarium recently formed, which bear a proportion to the aggregate of the entire collections of about one to nine.
Of the Australian portion of Mimoseae, which (having been met with upon all the coasts of the continent, and equally diffused in the interior) forms a leading characteristic of its vegetation, upwards of fifty species have been collected, in various stages of fructification; nearly the whole of which are unpublished plants. Several of those discovered on the north-western shores, and islands off the West Coast, being also extremely curious in their general form and habits; and the existence of a few appears limited to a solitary particular situation, and no one species was observed common to those parts, and the opposite or eastern shores of the continent.
The Papilionaceous division exceeds seventy species, two-thirds of which belong to established diadelphous genera, found chiefly within the tropic, where some, peculiar to Terra Australis, and heretofore limited to the more temperate regions, have been discovered. Thus Hovea and Bossiaea were detected in New South Wales, in latitude 20 and 22 degrees South, as well as on the North Coast; the latter genus being likewise found on the north-western shores, where also two species of Kennedia exist; and Templetonia, a genus nearly related to Bossiaea, originally discovered on the southern shores of Australia, is abundant on an island off the West Coast.
Upon the North-west Coast, particularly in the parallels of 14 and 15 degrees South, where an exotic feature (if the usual characteristic of the Flora of other countries might in this case be so termed) is as manifest, and is as strongly blended with the pure Australian character (Eucalyptus and Acacia) in its general vegetation, as on any other parts of those shores; Jacksonia and Gompholobium, genera of Papilionaceae, with distinct stamens, almost limited to the parallel of Port Jackson and the South Coast, were observed: Daviesia, almost wholly restricted to the higher Australian latitudes, has been remarked on the North Coast. Of Lomentaceae, Bauhinia, Caesalpinia, and the emigrant genus Guilandina, are all of intratropical existence in New South Wales, as also upon the North-west Coast; but Cassia, although it has an equal extensive range in the equinoctial parts of New Holland, has also been recently traced as far in the interior, on the parallel of Port Jackson, as the meridian of 146 degrees East.
EUPHORBIACEAE. The Herbarium contains thirty-three plants of this very numerous order, whose maximum seems decidedly to exist in India and equinoctial America. The whole of the Australian species are referable to established Linnean genera, of which Croton and Phyllanthus are most remarkable and numerous, existing on all the intratropical shores of Terra Australis, but by no means limited to them, both genera, together with Euphorbia and Jatropha, being found in the parallel of Port Jackson; and Croton exists likewise at the southern extreme of Van Diemen's Land, which is probably the limit of the genus on that hemisphere.
A Tragia (scarcely distinct from a species indigenous in India) is sparingly scattered on the East and North Coasts; and Acalypha has been remarked on these, as well as the north-western shores.
PITTOSPOREAE. Of this small family, whose characters and limits were first described by Mr. Brown, there are sixteen species in the Herbarium of these voyages, referable to Bursaria, Billardiera, Pittosporum, and two unpublished genera.
Billardiera, whose species are wholly volubilous, and which are not found north of the parallel of Port Jackson, is frequent on the South-west Coast, and has been recently remarked on the West Coast of Van Diemen's Land. Bursaria on the other hand, appearing limited to New South Wales, has been traced within the tropic to latitude 19 degrees South on those eastern shores, and although the genus Pittosporum is even more extensively diffused on that coast, it has not been met with upon the north-western shores, whilst the islands off the West Coast furnished me with two new species.
DIOSMEAE, although very frequent in the higher latitudes of Terra Australis, where they are so frequent as to give a peculiar character to their vegetable productions, is comparatively rare within the tropic; for upon the East Coast Eriostemon and Phebalium appear to be the only genera, the latter having been recently discovered, in about latitude 20 degrees South.