1182 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



tomentose beneath ; cymes pedunculate, lax, many-flowered, repeatedly dicho- 

 tomous ; flowers about 5 mm. long. 



12. Marsdenia mexicana Decaisne in DC. Prodr. 8: 617. 1844. 



Guerrero, Oaxaca, Morelos, and Mexico ; type from Tlacolula, Oaxaca. 



Large woody vine ; leaves broadly cordate, 8 to 16 cm. long, acute or short- 

 acuminate, tomentose beneath, densely pubescent above ; cymes pedunculate, 

 many-flowered, repeatedly branched; corolla about 4 mm. long; follicles 7 to 

 9 cm. long, densely pilose. 



16. TRICHOSACME Zucc. Abh. Akad. Wiss. Munchen 4": 11. 1845. 

 A single species is known. 



1. Trichosacme lanata Zucc. Abh. Akad. Wiss. Munchen 42: 11. 184.5. 



Described from Mexico. 



Scandent shrub, densely white-lanate throughout except on the corolla ; 

 leaves ovate-cordate, acute or acuminate, petiolate ; umbels axillary, dense, 

 pedunculate, recurved ; calyx lobes linear-lanceolate ; corolla rotate, brown- 

 purple, the lobes ovate, bearing at the apex a long filiform drooping barbate 

 appendage, this much longer than the lobes ; corona annular ; follicles cylin- 

 dric, tomentose. 



17. LACHNOSTOMA H. B. K. Nov. Gen. & Sp. 3: 198. 1819. 



1. Lachnostom.a g'onoloboides Greenm. Proc. Amer. Acad. 39: 84. 1903. 



Type collected near Seven Star Mine, in the Sierra Madre of Chihuahua, 

 altitude 2,400 meters. 



Stems twining, chiefly herbaceous, densely pubescent ; leaves long-petiolate, 

 oblong-hastate, 5 to 9.5 cm. long, short-acuminate, cordate at base, thinly hir- 

 tellous ; umbels short-pedunculate, mostly 2 to 4-flowered, the pedicels 2 to 3 

 cm. long ; calyx lobes oblong-lanceolate ; corolla white, narrowly campanulate, 

 1.5 to 2 cm. long, the lobes erect, acute; crown crenate. 



18. MICBODACTTLON' T. S. Brandeg. Zoe 5: 252. 1909. 

 The genus consists of a single species. 



1. Microdactylon ovatum T. S. Brandeg. Zoe 5: 252. 1909. 



Type from Barranca de Tlacuilosto, near San Luis Tultitlanapa, Puebla. 



Stems f ruiticose, scandent, hirsute and hirtellous ; leaves slender-petiolate, 

 ovate-cordate or oblong-ovate, 3 to 7 cm. long, rounded to acuminate at apex, 

 pubescent; cymes racemiform, long-pedunculate; calyx lobes lanceolate; co- 

 rolla purple-black, shallowly campanulate, about 2 cm. broad, hirtellous out- 

 side, long-hirsute within, the lobes deltoid-ovate, obtuse; corona adnate to the 

 stamen tube, the scales unguiculate, divided above the middle into 2 long 

 liguliform lobes, also with 2 shorter interior lobes. 



19. DICTYANTHUS Decaisne in DC. Prodr. 8: 604. 1844. 



Plants scandent or suberect, herbaceous or suffrutescent ; leaves cordate; 

 cymes few-flowered, racemiform or reduced to a single flower; flowers large, 

 the corolla reticulate-veined ; calyx 5-parted, glandular within, the lobes nar- 

 row; corolla broadly campanulate, the lobes spreading; corona scales attached 

 to the base of the stamen tube and radiating from it, adnate dorsally to the 

 corolla. 



