GREENMAN, — GENUS LIABUM. 293 
Nov. Gen. & Spec. iii. 386; Bot. Mag. 4223. -Zyinetia longiflora, Cav. 
Ic, vi. 51, t. 257, f. 1 
H. (MacronoustoniA) TRIFLORA, Gray, l. c., Hemsl. 1. ¢., is a good 
Bouvardia. 
From the technical characters of complete specimens of the last two 
species, now at hand, there seems no reason for retaining them in the 
genus Houstonia. 
Il. KEY TO THE MEXICAN SPECIES OF LIABUM. 
* Leaves ovate or ovate-deltoid: heads radiate. 
+ Leaves Lairanieaeaataa, more or less deeply sinuate-dentate and mucronate-denticu- 
late: heads few, large (3 to 5 cm. in diameter), terminating the stem 
L. Andrieuxii, Benth. & Hook. f. Gen. ii. 437. Vernonia eee 
DC. Prodr. y. 16. 
* + Leaves ovate, entire or mucronate-denticulate: heads disposed in terminal 
++ Pappus of slender unequal sete, not biseriate. 
= Involucral scales lance-attenuat petioles erat and often dilated about the 
stem: ligules narrow: achenes pubescent. 
L. asclepiadeum, Schz. Bip. Linnea, xx. 521. 
= Involucral scales oblong, obtuse: ligules ovate: achenes glabrous. 
L. polyanthum, Klatt, Bull. Soc. Bot. Belg. xxxi. (1892), 209. 
++ ++ Pappus distinctly biseriate, outer series short, paleaceous. 
= Achenes pubescent. 
L. andromachioides, Benth. & Hook. f. Gen. ii. 436. Vernonia 
andromachioides, Less. Linnea, vi. 397, 645. 
L. Deppeanum, Hemsl. Biol. Centr..Am. Bot. ii. 232. Andro- 
machia Deppeana, Less. a vi. 401. 
= Achenes glabrous. 
L. platylepis, Sche. Bip. Flora, 1856, 160; Klatt, Leopoldina, 
Xxiii. (reprint, p. Ty. 
L. Aiiclae Benth. & Hook. f. Gen. ii. 486. Sinelatria discolor, 
Hook. & Arn. Bot. Beech. 433; Hook. Ic. Pl. v. t. 451. 
* * Leaves ovate or ovate-lanceolate: heads discoid. 
* Inflorescence in loose terminal pyramidal panicles : involucre 3-5-seriate : 
appus biseriate. 
++ Immature achenes stipitate-glandular : involucral scales obtuse. 
L. glabrum, Hemsl. 1. ¢. 
