These two, or possibly three species, belong to the desert tracts of the South Australian interior. In the same regions we have another tribe of Cassiae closely allied to the aphyllous species; they have only one pair of foliola which are caducous, and whose persistent footstalk is more or less vertically compressed. Along with these, and nearly related to them, are found several species of Cassia, having from two to four or five pairs of foliola which are narrow, but their footstalks are without vertical compression, and their foliola are caducous, chiefly in those, however, which have only two pairs.
PETALOSTYLIS.
Caesalpinearum genus, Labicheae proximum.
CHAR. GEN.--Calyx 5-phyllus, aequalis. Petala 5 subaequalia, patentia. Stamina: Filamenta quinque sepalis opposita, quorum tria antherifera, antheris basifixis linearibus, duo reliqua castrata. Ovarium oligospermum. Stylus maximus, petaloideus, trilobus, lobo medio longiore axi incrassata desinente in stigma obtusum simplex!
Frutex glaber, erectus. Folia alterna, pinnata cum impari, foliolis alternis. Racemi axillares, pauciflori. Flores flavi.
13. PETALOSTYLIS Labicheoides.
LOC. "In the bed of a creek along with Sturtia." D. Sturt.
OBS. Eadem omnino species exstat inter plantas in Insulis Archipelagi Dampieri juxta oram septentrio-occidentalem Novae Hollandiae in itinere navis Beagle dictae lectas.
DESC. Frutex facie fere Cassiae et Labicheae. Folia alterna, cum impari pinnata, foliolis alternis brevissime petiolatis oblongolanceolatis cum mucronulo terminali paulo majore. Stipulae parvae caducae. Racemi pauciflori, axillares, folio breviores. Alabastrum ovali-oblongum acutiusculum. Calyx viridis, sepalis subaequalibus oblongis acutis, aestivatione imbricatis. Petala quinque subaequalia, oblonga, flava aestivatione imbricata, sepalis sesquilongiora. Stamina 3 antherifera aequalia, filamentis abbreviatis, antheris acutis bilocularibus, loculis sulco longitudinali insculptis; 2 reliqua rudimenta parva subfiliformia. Ovarium sessile, lineare, 3-4-spermum. Stylus lobo medio triplo longiore, oblongo-lanceolato, lobis lateralibus auriculiformibus semiovatis obtusis. Stigma imberbe.
OBS. The structure of the style, which forms the only important character of this genus, so far as the specimens enable me to judge, is so remarkable and peculiar, as to render it necessary to state, that I have found it quite uniform in all the flowers I have examined; namely, in four immediately before, and in three after expansion.