and it would be in vain to attempt a definition of an order composed of such heterogeneous materials. By the separation of the order here proposed it becomes at least practicable to define Onagrariæ. It is still however, difficult to characterise Halorageæ, which will probably be best understood by considering as the type of the order the genus Haloragis, from which all the others differ by the suppression of parts or separation of sexes. Thus Meionectes, an unpublished genus of New Holland, is reduced to half the number of parts both of flower and fruit. Proserpinaca is deprived of petals and of one fourth of all the other parts. Myriophyllum, which is monœcious, has the complete number of parts in the male flower, but in the female wants both calyx and corolla; what several authors have described as petals being certainly bracteæ.
Serpicula differs from Myriophyllum in having only half the number of stamina in the male flower, and in its unilocular four-seeded ovarium.
Hippuris, though retaining the habit of Myriophyllum, yet having a monandrous hermaphrodite flower without petals, and a single-seeded ovarium, is less certainly reducible to this order: and it may appear still more paradoxical to unite with it Callitriche, in which, however, I am inclined to consider what authors have denominated petals as rather analogous to the bracteæ in the female flower of Myriophyllum and Serpicula, and to both these genera Callitriche in the structure of its pistillum, and even in habit very nearly approaches.
The Australian genera of this order are Haloragis, Meionectes, Myriophyllum, and Callitriche.
Of Haloragis, many new species have been observed in Terra Australis, in every part of which this genus is found, most abundantly however at both extremities of the principal parallel.
That Gonocarpus really belongs to the same genus, I am satisfied from an examination of original specimens sent by Thunberg himself, to Sir Joseph Banks, for in these I find not only petals, but eight stamina and a quadrilocular ovarium.
LEGUMINOSÆ.[1] This extensive tribe may be considered as a class divisible into at least three orders, to which proper names should be- ↑ Juss. gen. 345.
