1052 CONTEIBUTIONS FROM THE NATIONAL HERBARIUM. 



0. Heterocentron alatum Rose & Standi., sp. nov. 



Type collected near San Juan Guichicovi, Oaxaca ( "Nelson 2728 ; U. S. Nat 

 Herb. no. 842869). 



Stems 4-angled, with a conspicuous green wing along each angle, ap- 

 pressed-setulose ; leaves slender-petiolate, elliptic-oblong or oblong-ovate, 3.5 

 to 6 cm. long, 1.5 to 2.3 cm. wide, acute, attenuate at base, pinnate-nerved, 

 appressed-setulose ; panicles many-flowered, the flowers short-pedicellate ; calyx 

 tube 3 mm. long, with a few short stiff hairs, the lobes 4 to 5 mm. long, ovate- 

 lanceolate, acuminate, obscurely cliolate; petals white, about 1 cm. long; 

 capsule 6 mm. long, the apical scales setose-ciliate. 



10. Heterocentron macrostachynm Naud. Ann. Sci. Nat. III. 14: 155. 18-50. 



Ileeria macrosiachya Triana, Trans. Linn. Soc. Bot. 28: 34. 1871. 



Veracruz and Oaxaca. Guatemala and El Salvador. 



Stems appressed-setulose, quadrangular ; leaves elliptic-ovate or ovate-oblong, 

 3 to 7 cm. long, obtuse or acute, attenuate at base; petals white or lilac, 

 7 to 8 mm. long. 



6. ACIOTIS D. Don, Mem. Wern. Soc. 4: 300. 1823. 



1. Aciotis rostellata (Naud.) Triana, Trans. Linn. Soc. Bot. 29: 51. 1871. 

 Spennera rostellota Naud. Ann. Sci. Nat. III. 14: 143. 1850. 



Tabasco. Guatemala and Nicaragua. 



Stems herbaceous or suffrutescent, 30 to 60 cm. high, acutely tetragonous, 

 shortly glandular-pilose above; leaves ovate-oblong, 7-nerved, 5 to 7 cm. long, 

 acuminate, pilosulous, entire ; flowers 4-parted, paniculate ; calyx 1.5 mm. long ; 

 petals white, 2 mm. long; capsule 2.5 mm. thick. 



7. SCHWACKAEA Cogn. in Durand, Ind. Gen. Phan. 132. 1888. 



The genus consists of a single species. 



1. Schwackaea cupheoides (Benth.) Cogn. in Durand, Ind. Gen. Phan. 132. 

 1888. 



Heeria cupheoides Benth. Bot. Voy. Sulph. 93. pi. 33. 1844. 



Pterogastra cupheoides Seem. Bot. Voy. Herald 122. 1854. 



Acisanthera simplex T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 57. 1914. 



Oaxaca and Chiapas. Central America ; type from Panama. 



Slender annual, 10 to 30 cm. high, the branches setulose at the nodes, else- 

 where glabrous ; leaves petiolate, ovate, 3 to 6 cm. long, acute, 3-nerved, entire, 

 pilosulous ; flowers 4-parted, solitary or in terminal cymes ; calyx in fruit 1 

 cm. long, the tube with 8 thick ribs, these setose-tuberculate ; petals 6 to 7 

 mm. long. " Sulfatillo," "sulfate de la ^erra," "pollito" (El Salvador). 



8. PTEROLEPIS Miq. Comm. Phytogr. 73. 1840. 



Herbs, rarely suffrutescent ; leaves entire, 3 or 5-nerved ; flowers 4-parted, 

 small, axillary or terminal, solitary or glomerate ; calyx lobes rigid, persistent, 

 alternating with bristles ; petals obovate, obtuse, ciliate ; capsule 4-valvate. 



Connective of the larger anthers much shorter than the anther 1. P. exigua. 



Connective nearly as long as the anther. 



Anthers linear-subulate; calyx tube 4 mm. long 2. P. trichotoma. 



Anthers oblong; calyx tube 2 to 2.5 mm. long 3. P. pumila. 



1. Pterolepis exigua (Naud.) Triana, Trans. Linn. Soc. Bot. 28: 39. 1871. 

 Arthrostemma exiguum Naud. Ann. Sci. Nat. III. 13: 355. 1850. 

 Oaxaca and Chiapas; type from mountains of Oaxaca. Costa Rica. 



