ia 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.

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