716 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



I/eaves sessile, cordate at base 1. K. umbellata. 



Leaves petiolate, rounded or obtuse at base. 



Flowers densely pubescent ; leaves pubescent beneath. 

 Nerves impressed on the upper surface of the leaf; leaves finely and densely 



puberulent above 2. K. mollis. 



Nerves not impressed ; leaves glabrate above 3. K. pubescens. 



Flowers glabrous; leaves glabrous beneath. 



Petioles 1 to 3 cm. long ; leaves mostly 3 to 5.5 cm. wide, usually rounded and 



mueronate at apex 4. K, latifolia. 



Petioles less than 1 cm. long, usually less than 7 mm. ; leaves mostly 1 to 2 

 cm. (rarely 3 cm.) wide, not conspicuously mueronate. 



5. K. humboldtiana, 



1. Karwlnskia umbellata (Cav.) Schlecht. Linnaea 15: 460. 1841. 

 Rhamnus umhellata Cav. Icon. PI. 6: 2. pi. SOJ/. 1801. 

 Karwinskia sessllifolia Schlecht. Linnaea 15: 461. 1841. 



Michoacjln and Guerrero ; type collected between Chilpancingo and Rfo Azul, 

 Guerrero. 



Glabrous shrub or small tree, 1 to 4.5 meters high ; leaves elliptic-ovate, 4 to 

 8 cm. long, obtuse or rounded at apex, the transverse veins very prominent 

 beneath ; umbels pedunculate, few-flowered ; flowers green ; fruit 7 to 8 mm. in 

 diameter. 



2. Karwinskia m.ollis Schlecht. Linnaea 15: 461. 1841. 



Quer§taro, San Luis Potosf, and Veracruz ; type from Barranca de Santa 

 Maria. 



Shrub ; branches densely pilosulous ; leaves short-petiolate, oblong to elliptic, 

 1.5 to 4.5 cm. long, obtuse or rounded at apex, flnely and densely pubescent on 

 both surfaces, the lateral nerves close and parallel, very prominent beneath; 

 umbels usually sessile, often reduced to a single flower; fruit 7 to 9 mm. in 

 diameter. 



3. Karwinskia pubescens Standi., sp. nov. 



Baja California and Sonora to Oaxaca, and Coahuila ; type from Hermosillo, 

 Sonora {Malthy 215; U. S. Nat. Herb. no. 314960). Western Texas. 



Slender shrub, about 1 meter high, the branchlets puberulent; leaves short- 

 petiolate, oblong to ovate or elliptic, 2 to 4.5 cm. long, obtuse or rounded at 

 base and apex, thin, beneath puberulent or thinly pilosulous, glabrate above, 

 the lateral nerves usually few and distant ; umbels sessile or short-pedunculate, 

 densely pubescent; fruit 5 to 7 mm. in diameter. " Coyotillo " (Texas). 



This may be only a form of K. humboldtiana,, but it appears fairly distinct. 



4. Karwinskia latifolia Standi., sp. nov. 



Sinaloa, Tepic, and Jalisco; type from Tepic {Palmer 1848; U. S. Nat. Herb, 

 no. 30.5562). 



Shrub or small tree, sometimes 6 meters high, glabrous throughout; leaves 

 lance-oblong to broadly ovate-elliptic, 6, to 11 cm. long, rounded or obtuse at 

 base, usually rounded at apex and mueronate, thin, pale beneath, the lateral 

 nerves comparatively few and distant; umbels pedunculate; fruit 7 to 10 mm. 

 long. "Margarita" (Jalisco). 



This is the plant reported by Hooker and Arnott * as Rhamnus binifiorus 

 var. ?, and referred doubtfully by Schleehtendal " to K. afflnis. The leaves in 

 some specimens are strikingly suggestive of those of certain species of Cornus. 



*Bot. Beechey Voy. 283. 183&-39. 

 'Linnaea 15: 460. 1841. 



