264 



ORCHIDACEJE 



M. NELSONII sp nov. Aff. Microstylidi ochreatce Watson. 

 Herb a gracilis, diphylla, usque ad 43 cm. alta. Folia oblongi- 

 lanceolata, obtusa vel subacuta, 4.5-7 cm. longa, 1.5-2.5 cm. lata, 



infra medium caulem orta, ad basim 

 vaginantia. Injiorescentia multiflora, 

 laxa, circa 12 cm. longa et 1 cm. in dia- 

 metro. Bractece triangulares, acutae, 2 

 mm. longae. Pedicellus cum ovario 4.5 

 mm. longus. Sepala lateralia oblonga, 

 obtusa, ad apicem fastigata, 3-nervia, 3 

 mm. longa, circa 1 mm. lata. Sep alum 

 dorsale simile. Petala linearia, obtusa, 

 1-nervia, 3 mm. longa. Labellum trulli- 

 forme, explanatum ovato-lanceolatum, 

 Ma t.axt s Xelsond acuminatum, obtusum, 2.5 mm. longum. 



M.Nelsonii differs from Microstylis ochreata Watson, to which 

 it is nearly allied, in having a trulliform labellum. The labellum 

 of M. ochreata is sagittate. 



Type (no. 332832 in National Herbarium) from Sierra Madre, 

 30 miles north of Gunacevi, alt. 8000-9000 ft., State of Durango, 

 Mexico, August 18, 1898, E. W. Nelson (no. 4782). 



M. SPICATA Swartz Prodr. 119 (1788) and Fl. Ind. Occ. 3: 

 1441, t. 28, figs, a, b, c (1799) ; Microstylis spicata Lindley Orch. 

 PL 19 (1830) ; M. floridana Chapman Fl. S. U. S. ed. 1, 454 

 (1860), Ames Contr. Orch. Fl. Fla. p. 15, t. 6 (1904) ; Acroan- 

 thes floridana Greene Pittonia 2: 183 (1891). — The analysis of 

 the flower given by Swartz in Fl. Ind. Occ. is not at all satisfac- 

 tory. The lobes of the labellum are over-accentuated, and the 

 laterals are drawn acute. The Jamaican specimen in the herbarium 

 of the British Museum collected by Swartz is rather taller than the 

 average. 



