334 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN [Vql 8, No. 4 



oblong, puberulous on the margins, laterally glabrous, 4-ovulate; free portion of 

 the gynophore 2 mm. long, minutely puberulous. Fruit unknown. 



Type Collection: H. Pittier 23975, "Selvas inferiores del valle de Ocumare 

 (Parque nacional) 600 m.," Aragua, Venezuela, April 1937 (HOLOTYPE VEN, 

 isotype US). 



Additional Specimens: VENEZUELA: Prope coloniam Tovar, between Valencia and 

 Campanero, July or March 1857, Fendler 2414 (GH); Parque Nacional, between Rancho 

 Grande and Maracay, Aragua, Dec. 1943» Steyermark 54963 (F, MO, VEN). 



Macrolobium obtusum is perhaps most closely allied to M. floridum which was 

 described from this same general area of Venezuela. However, M. obtusum may be 

 distinguished by the broadly rounded leaflet apices, by its smaller bracts and 

 petal and by its generally shorter hypanthium. 



47. Macrolobium archeri Cowan, sp. nov. Figure 12. 



Alta arbor vel gracile arbustum 5 ra. altum, ramulis glabris vel microscopico- 

 puberulis. Folia glabra; petiolus 2-6 mm. longus, subsulcatus ad canaliculatus, 

 glaber vel minute puberulus. Foliola 21.5*50 cm. longa, 6-11 cm. lata, subaequi- 

 lateralia, elliptica, ad basim inaequilateralia, latere superiore acuto et inferiore 

 rotundato-obtuso, ad apicem acuminata et extremitate obtusa vel acuta, infra punc- 

 tata; costa salienti sed infra validiore, venulis obscuris ad prominulis. Inflores- 

 centiae ca. 3.5 cm. longae, terminales, axe minutissime puberulo; bracteis 3 rani, 

 longis, 1.5-2 ram. latis, persistentibus, triangulari-ovatis, acuminatis, ciliolatis, 

 intus glabris, extus minuto-puberulis; bracteolae 17 mm. longae, 6.5 ram. latae, 

 obovatae, rotundato-obtusae, coriaceae, concavae, intus glabrae, extus sparse 

 minutissimeque puberulae vel glabrae. Hypanthium 14 mm. longum, stipite 4.5 ram. 

 longo, glabrum, carnosum. Sepala 20-22 mm. longa, 4.5*7 mm. lata, oblonga, ob- 

 tusa, concava, carnoso-coriacea, glabra. Petalus 28 mm. longus, 12 mm. latus, 

 lanceolatus, sessilis, glaber. Filamenta 27 mm. longa, basim versus pilosa, an- 

 therae obiongae, 9-10 mm. longae, 2.5 ram. latae. Stigma capitatum. Stylus ca. 21 

 mm. longus, glaber. Ovarium 5-7 mm. longum, 2 mm. latum, oblongum, marginibus 

 sparse puberulis sed lateraiiter glabrum, 5-ovulatum, gynophori parte libera 5 mm. 

 longa. Fructus ignotus. 



Type Collection: W. A. Archer 2020, "Intendencia del Choco: Quibdb, Rio 

 Atrato; altitude about 60 meters," Colombia, April-May 1931 (HOLOTYPE US, 

 fragmentary isotype NY). 



Additional Specimens: COLOMBIA: Rio Atrato, Quibdo, Intend, del Choco, April-May 

 1931, Archer 2023 (US); Rio Calima (region del Choco), La Trojita, 5-50 m. alt., Feb.- 

 March 1944, Cuatrecasas 16309 (F); Cordoba, valley of Rio Dagua, Dept. El Valle, Oct. 

 1922, Killip 11852 (NY, US); south of Rio Condoto, between Quebrada Guarapo and Man- 

 dinga, ^ntend. El Choco, April 1939, Killip 35433 (US); Puerto de Buenaventura, April 

 1833, Triana s.n. (COL); Port de Buenaventura, 1851-57, Triana s.n. (P). 



Both morphologically and geographically the nearest relative of this species 

 is the Panamanian species M. pittieri. The sessile petal of M. archeri is much 

 smaller than that of its relative; it has a very much stouter hypanthium, which is 

 longer; its bracteoles are considerably larger and puberulous on the outer surface; 

 the leaflet apex of M. archeri is bluntly acuminate but it is caudate-acuminate in 

 M. pittieri. All these differences add up to a marked series of distinctions between 

 the two species. 



All the material cited above had been identified previously as M. floridum, 

 which, while closely related, is quite different, judging from the meagre data avail- 

 able. M. floridum exhibits the following differences: (1) acute leaflet apices rather 

 than acuminate; (2) a longer inflorescence; (3) sepals about 10 mm. long as com- 

 pared to 20 mm.; and (4) a pubescent hypanthium. 



