24 ON SOTJTH-AMBEICAX APOCYNACEiE. 



2. Thykoma decipiens, nob. : Aspidosperma decipiens, Miill. /. c. p. 398. In Venezuela; v. s. in herb. 



meo et aliorum Rio Maypure, Rio Orinoco (Spruce 3657) . 

 A species near the preceding, with slender verruculose hranches, having opposite, or 

 by abortion alternate axils, 3^ lines apart : the oblong-ovate leaves, with rounded or 

 emarginated summits, are 2 in. long, 1 in. broad, on a slender petiole 3 lines long ; they 

 are shining and glabrous above, with about 15 pairs of nerves, yellowish opake beneath, 

 obsoletely tomentous under a lens, with prominent midrib and nerves : the panicle is 

 6 lines long, with about 4 alternate branches 3 lines long, bearing few flowers on very 

 short pedicels ; the structure of the flower as in the foregoing species. 



3. Thyroma nitida, nob. : Aspidosperma nitidum, Bentb. MS. ; Miiller in Mart. Fl. Bras. fasc. 26. 



p. 59. In Amazonas : v. s. in hb. meo et alior. Barra do Rio Negro (Spruce 1657) . 

 A species, compared with the two former, inaptly called nitida : the axils of the sub- 

 angular verruculose branchlets are ^— | in. apart : the opposite leaves, often alternate, 

 are oblong, obtuse, subcoriaceous, with somewhat revolute margins, are 24-3 in. long, 

 l^lf in. broad, on a petiole 3^-4 lines long, they are green, subopake above, closely 

 impressed-punctate, and with about 16 pairs of nerves, of a yellowish dirty white 

 beneath, with an impressed scrobiculate surface, with prominent midrib and sulcated 

 nerves : the axillary panicle, densely corymbose, on a bifurcated peduncle 4 lines long, 

 bearing 2 capitate heads of small flowers, 4-5 lines in diameter ; the pedicels are f Hne 

 long, with 3 short cUiated bracts at base : the oval subacute sepals, puberulous outside, 

 are f line long; the corolla, 2 lines long, has a tube half that length, with border- 

 segments lanceolate-oblong, nearly erect, subfleshy and sinistrorsely convoluted ; disk, 

 ovary, style, and stigma as in the typical species. 



4. Thyroma polyneuka, nob. : Aspidosperma polyneurum, Miill. in Mart. Fl. Bras. /. c. p. 57. In 



Brasilia, prov. Rio de Janeiro: v. s. in hb. Hook. (Sellow 632), Corcovado (Gardn. 5363). 



A tree 80 feet high, giving a useful timber called " peroba," with a bitter bark : the 

 specific name was applied because of its numerous fine parallel nerves, about 60 pairs, 

 united by a common line within the revolute margin, and with fine reticulations between 

 them: the leaves, sometimes subopposite, more often alternate, are glabrous, sub- 

 membranaceous, elliptic, obtuse at the summit, gradually acute below, 2J-3^ in. long, 

 |-1 in. broad, on petioles 4-5 lines long: the panicle is 9-10 lines long, with few 

 branches and few flowers ; the pedicel is 1 line long, the calyx f line, corolla 3 lines 

 long, tube narrowed gradually below, puberulous outside, retrorsely pilose inside, with 

 5 oblong obtuse erect segments, sinistrorsely convoluted, pilose within, f length of tube ; 

 5 small scales within the mouth of the tube opposite the segments ; 5 short stamens beneath 

 and alternate with the scales, anthers cordate at the base, on very short filaments : follicle 

 single, very much flattened, straight on the dorsal side, semioblong on the other, both 

 ends acute, 15-21 lines long, 4^5 lines broad ; seeds scutellate and tomentellous at the 

 upper moiety, broadly winged and glabrous below. 



5. Thyroma Sellowii, nob. ; Aspidosperma Sellowii, Miill. ibid. p. 56. In Brasilia meridionali : v. a. 



in hb. Hook. (SeUow 1204). 



The leaves are Hke those of the preceding, but with only 10 pairs of immersed nerves, 



