98 ON SOUTH-AMERICAN APOCYNACEA. 
ceous under a lens, otherwise, according to Jacquin and De Candolle, without a coma 
Swartz says they have a setose pappus, meaning their setosely hairy covering. Grise- 
bach states they have a rusty coma; but that applies to his Forsteronia Alexandri. 
The flower, beyond all doubt, belongs to Thyrsanthus, and not to Forsteronia. 
11. THYRSANTHUS CORYMBIFERUS, nob. : Thenardia ? corymbosa, Benth. Hook. Journ. Bot. ui. 246: 
Forsteronia corymbosa, Mey. Esseq. p. 134, excl. synon. (non A. DC. nec Griseb.) : Forsteronia 
Schomburgkii, A. DC. l. c. p. 438 (non Benth.) : Forsteronia lancifolia, Müll. (in parte), l. c. p. 106. 
In Guiana (Schomb. 247) : non vidi. 
This certainly is not a Thenardia; but it accords with the genus Thyrsanthus of 
Bentham, and is near the preceding species. It is subscandent, with smooth branch- 
lets somewhat pilose at the summits; leaves oval-oblong, obtuse and subcordate at the 
base, narrowly obtuse and mucronate at the apex, membranaceous, glabrous above, with 
glands at the base of the midrib, as in T. Schomburgkii, subglabrous beneath, reticulated, 
2-8 in. long, 1-1} in. broad, on puberulous petioles; panicle terminal, short, densely 
flowered; flowers on pedicels shorter than the calyx; sepals lanceolate, without an 
internal scale; tube of corolla short, with a pilose staminiferous ring in the mouth; 
segments acute; anthers long, exserted, with 2 basal obtuse forks. 
12. THYRSANTHUS AUBLETIANUS, nob.: Apocynum umbellatum, Aubl. Pl. Guian. i. p. 275, tab. 108: 
Forsteronia Schomburgkii, var. umbellata, A. DC. l. c. p. 438: Thenardia umbellata, Spreng. Syst. 1. 
636; G. Don, Dict. iv. 80. . In Cayenne : non vidi. 
A sarmentose species, very distinct from 7. Schomburgkii. The leaves, according to 
Aublet, are rounded at the base, terminated by a long acumen, 24-84 in. long, 1-14 in. 
broad, smooth above, cinereo-tomentous below, on petioles 3-4 lines long; eorymb ter- 
minal, 1 in. long and broad, on a naked peduncle 9 lines long, with many flowers sub- 
umbellate on the ends of its branchlets, which are 2-bracteolated at their base, the pedi- 
cels being also bracteolated ; flowers 2 lines long, of a reddish colour; tube of corolla 
short; the segments rounded-oblong; stamens inserted in the mouth of the tube; 
anthers adhering to the clavuncle. 
Aublet's specific name has not been adopted, to prevent confusion with the Echites 
umbellata of Jacquin, or that of Kunth. 
13. TuvzsawTHUs Acovci, nob.: Apocynum Acouci, Aubl. l. c. p. 274, tab. 107: Apocynum apiculatum, 
Lam. Dict. i. p. 214: Forsteronia Acouci, A. DC. Prodr. viii. p. 437. In Guiana: v. s. in herb. Mus. 
Brit. Cayenne (Aublet). 
This is a scandent species, with slender glabrous branchlets. Its lanceolate oblong 
leaves, horizontally spreading, are somewhat acute at their base, constricted above into 
an obtuse acumen, thinly chartaceous, with subrevolute margins, palish green and opake 
above, glauco-pulverulent, closely granulated with dark polished dots, semi-immersed fine 
nerves, and sulcate upon the finely reticulated veins, with 2 small yellow glands at the 
base of the midrib, lateritious and opake beneath, with prominulent nerves, 34—4 in. 
long, 1-13 in. broad, on deeply channelled petioles 1 line long; panicles terminal and 
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