OBS. The genus Eremophila was founded on very unsatisfactory materials, namely, on two species, E. oppositifolia and alternifolia, which I found growing in the same sandy desert at the head of Spencer's Gulf in 1802, the only combining character being the scariose calyx, which I inferred must have been enlarged after flowering. This, however, proves not to be the case in E. alternifolia, which Mrs. Grey has found in flower towards the head of St. Vincent's Gulf: and from analogy with other species since discovered, it probably takes place only in a slight degree in E. oppositifolia, whose expanded flowers have not yet been seen.
In 1817, Mr. Cunningham, in Oxley's first expedition, discovered a third and very remarkable species in flower and unripe fruit, which he referred, with a doubt, to Eremophila, and which M. Alphonse De Candolle has recently separated, but as it seems to me on very insufficient grounds, with the generic name of Eremodendron, established entirely on Mr. Cunningham's specimens. A fourth species has lately been described by Mr. Bentham, in Sir Thos. Mitchell's narrative of his Journey into Tropical Australia; and some account of a fifth is given in the following article.
These five species may be arranged in four sections, distinguished by the following characters:
a. Folia opposita; sepala unguiculata. Eremophila oppositifolia. Br. prodr. 1. p. 518.
b. Folia alterna; sepala unguiculata, eglandulosa; antherae exsertae.
E. Cunninghamii.
c. Folia alterna; sepala breve unguiculata, eglandulosa; stamina inclusa.
Eremophila Mitchelli. Benth. in Mitch. trop. Austr. p. 31. Eremophila Sturtii.
d. Folia alterna glanduloso-tuberculata, sepala cuneato-obovata, sessilia, glandulosa.
E. alternifolia. Br. prodr. i. p. 518.