VOLUME LXX NUMBER 2 



Reprinted for private circulation from 

 The Botanical Gazttee, Vol. LXX, No. 2, August 1920 



« ■"' •'Of* 



Botanical Gazette 



AUGUST 1920 

 STUDIES IN THE GENUS BIDENS. V 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 269 



Earl E. Sherff 

 (WITH PLATES XI-XIV) 



Bidens exigua, sp. nov. (pi. XI). — Herba annua, 1.5-3 dm. alta; 

 caule tenuissimo, subrecto, striate, silbsimplici. Folia opposita 

 (summa alternata), membranacea, petiolata, petiolo adjecto 3-5 cm. 

 longa, bipinnata, glabra; foliolis (3 aut 5) maximam partem 

 3-5-partitis; lobis integris, subobtusis, inflrme apiculatis. Petioli 

 0.5-2 cm. longi, basi connati. Capitula pauca aut solitaria, dis- 

 coidea, tenuiter pedunculata pedunculis 2-5 cm. longis, ad anthesin 

 5-6 mm. longa et 1.5-2 mm. lata infra, 2-3 mm. lata supra; in 

 fructu, circ. 9 mm. longa et 2-5 mm. lata. Involucrum basi 

 sparsim hispidum aut glabratum; bracteis duplici serie dispositis; 

 exterioribus (4-7) linearibus, 2-3 mm. longis, ciliatis, ad faciem 

 glabris aut pubescentibus, ad apicem induratis; interioribus dimidio 

 longioribus, glabratis, lanceolatis, striatis, margine diaphanis. 

 Achaenia (submatura) linearia, glabra aut supra ad margines 

 remote hispida, bi- aut triaristata aristis retrorsum hamosis hamis 

 tenuibus, 4-8 mm. longa. 



Specimens examined. — C. H. T. Townsend 1513, alt. 1607 m., Chosica 

 Canyon, Peru, April 20, 1913 (Herb. U.S. Nat. Mus., no. 602943, type). 

 ,__ The plants of the type sheet would seem at first to be merely depauperate 

 CNJ or impoverished forms of some species normally larger and perhaps already 

 t— described. The technical characters, however, do not match those of any other 

 o^ species known to me. There are several species very close to B. exigua all of 



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