170 
COMPOSITE. 
* Tridax procumbens, Linn. ; DC. Prod. v. 679, a native of Mexico 
and the "West Indies, escaped from the Botanic G-arden at Pample- 
mousses about 1840, and is now spread through Mauritius by roadsides, 
and has reached Plat Island, Eodriguez, and Bourbon. It is a trailing 
perennial, branched in the lower part, with branches and leaves 
scabrous with short bristly hairs, opposite petioled rhomboid-deltoid 
deeply toothed acute simple leaves, few middle-sized many-flowered 
heads on very long peduncles, scales of the involucre subequal 2-3 serial, 
outer scabrous ovate-lanceolate acute herbaceous, inner membranous, 
obtuse ligulate, receptacle scaly, a few outer flowers with yellow ligules, 
anthers not tailed, receptacle scaly, achenes pilose angular-cylindrical, 
pappus of a single row of persistent densely plumose bristles. Herbe 
Caille. 
14. PSIADIA, Jacq. 
Heads heterogamous, the outer flowers female with a short entire 
or 2-3-cleft ligule, and the inner tubular and often abortive, all yellow. 
Involucre campanulate ; scales linear, 2-3-serial, unequal. Beceptacle 
alveolate. Anthers not tailed. Achenes very minute, glabrous, angu- 
lato-cylindrical ; pappus of numerous slender bristles, longer than the 
achene. — Glutinous shrubs, with alternate leaves and copious minute 
heads in dense terminal corymbs. Distrib. Tropical Africa, Mada- 
gascar, Bourbon, Cape. Species about a dozen. 
Leaves distinctly 3-, or in the broader forms 5-nerved from 
the base above the middle 1. P. trinervia. 
Leaves penninerved. 
Glabrous and glutinous. 
Leaves oblanceolate, obtuse, entire 2. P. penninervia. 
Leaves oblong-lanceolate, acute, inciso-dentate . . * P. glutinosa. 
Pilose, not glutinous 3. P. rodriguesiana. 
1. P. trinervia, Willd. Mag. Perl. 1807, 139. A low shrub, 
with glutinose branchlets and leaves. Leaves crowded, oblong, 
subcoriaceous, obtuse, 1-2 in. long, entire, with two distinct 
side veins running from the base nearly to the top, narrowed at 
the base into a petiole \ in. long. Blowers in dense terminal 
corymbs, 10-12 in a head. Involucre campanulate, in. long 
and broad ; scales linear, pale green, scariose, outer short. Achenes of 
outer flowers under in. long ; setae twice as long as the achene. P. 
integerrima, DC. Prod. v. 319. 
Far. linearifolia, (DO. Prod. loc. cit., as a species). Leaves linear, 
narrowed to both ends, petioled, entire, 2-3 in. long, under \ in. broad. 
Blowers in a head 10-12. 
Far. dentata (j DC. Prod. loc. cit.) Leaves petioled, lanceolate, 
inciso-dentate. Heads rather larger, and flowers in a head more 
numerous. 
Far. lanceolata, Baker. Leaves more membranous, lanceolate, 
entire, 3-4 in. long, an inch broad at the middle, narrowed to both ends. 
Heads of the type, containing ten or a dozen flowers. 
