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.
TRIBULOPIS.
Calyx 5-partitus deciduus. Petala 5. Stamina decem (nunc 5.) Filamenta quinque, sepalis opposita, basi glandula stipata. Ovaria 5, monosperma. Cocci, praeter tubercula 2 v. 4 baseos, laeves.
Herbae annuoe prostratoe; foliis omnibus alternis!
TRIBULOPIS (Solandri.) foliis bi-trijugis, foliolis subovatis inaequilateris, coccis basi quadrituberculatis.