COMPOSITE. 207 
17. Calea urticzfolia, DC. Prodr. v. p. 674. 
Caleacte urticefolia, R. Br. in Trans. Linn. Soc. xii. p. 109. 
South Mexico, Vera Cruz (Linden, 1184; Galeotti, 2233), Orizaba (Botteri, 481, 
1154), Tantoyuca (Ervendberg). Hb. Kew. 
18. Calea zacatechichi, Schl. in Linnea, ix. p. 589. 
Sour Mexico, Vera Cruz to Orizaba (Miiller), Vera Cruz (Linden, 1186; Galeotti, 
2235), valley of Cordova and Cuernavaca (Bourgeau, 1559,1218). Hb. Kew. 
145. TRIDAX. 
Tridax, Linn. Gen. Plant. n. 972; Benth. et Hook. Gen. Plant. i. p. 392. 
An endemic Tropical-American genus, comprising about ten herbaceous species, one 
of which is naturalized in India and Mauritius. 
1. Tridax balbisioides, A. Gr. in Proc. Amer. Acad. xv. p. 39. 
Galinsogea balbisioides, H. B. K. Nov. Gen. et Sp. iv. p. 253, t. 386. 
Sogalgina balbisioides, Cass. Dict. xlix. p. 398. 
Sour Mexico, between the valley of Santiago and Lake Palangeo, 5500 feet (Hum- 
boldt & Bonpland). 
Dr. A. Gray doubtfully refers Parry and Palmer’s no. 509 to this species, although it 
has three-cleft instead of entire ligules. 
2. Tridax bicolor, A. Gr. Pl. Fendl. p. 104. 
Norra Mexico, Chihuahua (Thurber), Sierra Madre ( Wislizenus). 
3. Tridax brachylepis, Hemsley, n. sp. 
Parce pilosula, foliis crassiusculis ovato-lanceolatis, capitulis discoideis (an semper ?) longissime 
pedunculatis, paleis quam flores multo brevioribus, pappi squamis brevibus. 
Herba annua, erecta, ramis gracilibus, glabrescentibus. Folia breviter petiolata, crassiuscula (ut 
videtur subcarnosa, venis obsoletis), ovato-lanceolata, 1-2 poll. longa, obtusa, remote calloso- 
dentata, interdum obscure lobata, utrinque parce pilosula. Capitula discoidea, flava (ex 
Galeottio), parva; involucri bractez glabrz, coriaceo-scariose, ovato-oblonge, apice obtu- 
sissime vel rotundate, purpures vel rosex, exteriores breviores; receptaculum conicum ; 
paleze floribus fere dimidio breviores, membranacez, glabre, striate, trifide ; corolle anguste 
infundibuliformes, extus deorsum sericeo-villose. Achenia appresse sericeo-villosa; pappi 
squame numerose, breves, plumosz. 
Soutn Mexico, Cordillera of Oaxaca, 7000 feet (Galeotti, 2024). Hb. Kew. 
4. Tridax candidissima, A. Gr. in Proc. Amer. Acad. xv. p. 39. 
Nort Mexico, region of San Luis Potosi, 6000 to 8000 feet (Parry & Palmer, 510). 
Hb. Kew. . mS 
5. Tridax coronopifolia, Hemsley. 
Ptilostephium coronopifolium, H. B. K. Nov. Gen. et Sp. iv. p. 255, t. 387. 
Nort Mexico, region of San Luis Potosi, 6000 to 8000 feet (Parry & Palmer, 508) ; 
