DESC.  Suffrutex orgyalis glaber.  Folia ramorum alterna, diametro unciali, trinervia; petiolo folium subaequanti, basi in stipulam subscariosam adnatam dilatato.  Pedunculi vel potius rami floriferi suboppositifolii nec vere axillares uniflori, juxta apicem folio nano petiolato stipulis 2 distinctis stipato instructi.  Involucrum foliaceum venosum, foliolis distinctis, cordatis, punctis nigricantibus glandulosis conspersis.  Calyx dentibus acutis, sinubus rotundatis.  Petala sesquipollicaria, uti calycis tubus glanduloso-punctata glandulis nigricantibus semi-immersis, purpurea basibus atro purpureis margine barbatis.  Columna staminum e basi nuda super ad apicem usque antherifera:  antheris reniformibus, loculis apice confluentibus.  Pollen hispidum.

OBS.  Sturtia is no doubt very nearly related to Gossypium, from which it differs in the entire and distinct leaves of its foliaceous involucrum, in the sharp teeth and broad rounded sinuses of the calyx, and possibly also in its fruit and seeds, which are, however, at present unknown.  They agree in the texture and remarkable glands of the calyx, and in the structure of the columna staminum.  Senra, which like Sturtia, has the foliola of its three-leaved involucrum distinct and entire, differs from it in having its calyx 5-fid with sharp sinuses, in the absence of glands, in the reduced number of stamina, and in its dispermous ovaria.

3.  Tribulus (Hystrix) lanatus, foliis 8-10-jugis, fructibus undique tectis spinis subulatis longitudine inaequalibus:  majoribus sparsis longitudinem cocci superantibus.

LOC.  “In collinis arenosis.  Lat. 26 degrees.”  D. Sturt.

DESC.  Herba diffusa, sericea, incana.  Folium majus cuiusque paris 8-10 jugum, foliolis ovatis.  Flores magni.  Calyxaestivatione leviter imbricata.  Petala calyce duplo longiora.  Stamina decem, antheris linearibus.

OBS.  I. A species nearly related to T. Hystrix, found on the west coast of Australia, or on some of its islands, in the voyage of the Beagle, may be distinguished by the following character.  Tribulus (occidentalis) sericeolanatus, foliis suboctojugis, coccis undique dense armatis:  spinis omnibus conico-subulatis longitudine invicem aequalibus.  These two species differ from all others in the uniform shape of the spines, which equally cover the whole external surface of the fruit.

OBS.  II.  The American species of the Linnean genus Tribulus are distinguishable from the rest of the published species, by having ten monospermous cocci, by their persistent calyx, and the absence of glands subtending the 5 filaments opposite to the sepals.

This tribe was originally separated as a genus by Scopoli, under the name of Kallstroemia, which has been recently adopted by Endlicher.

Another tribe exists in the intratropical part of the Australian continent, to which, nearly 40 years ago, in the Banksian Herbarium, I gave the generic name of Tribulopis, and which may readily be distinguished by the following characters.