

* 



I 



► 



1920] SHERFF— BIDENS 105 



Bidens torta, sp. nov. — Fruticosa, glabra, caule non crasso 

 dm. alta. Folia tripartita, membranacea, serrata, ciliata, 



• tenerrime 



cm. longa et 2 , s-10 cm. 



acuminatis, terminali multo maiore 



lateralibus sessilibus aut breviter petiolulatis, ovato-lanceolatis, 

 petiolis 1-4 cm. longis. Capitula numerosa, laxe paniculata, 

 mediocria, ligulata, ad anthesin circ. 5 mm. alta et 1 . 7 mm. lata. 

 Involucri bracteae exteriores circ. 5, tenuiter lineares, glanduloso- 

 pubescentes, 1.5-2.5 mm. longae, interioribus paulo breviores. 

 Ligulae circ. 5, oblongo-oblanceolatae, flavae, ad apicem plus 

 minusve dentulatae, circ. 7 mm. longae. Achaenia tenuiter 

 I linearia, nigra, maxime torta, glabra, corpore 9-13 mm. longa 



ad apicem calva aut obscure 1 

 (o . 1-0 . 3 mm. longis). 

 Specimens examined 



brevissimis 



March 



Mus 



thickne 



in proportion 

 dm. lone: and 



4 . 4 cm. wide. The branches of the inflorescence are slender and widely 

 diverging. The leaves and inflorescence combine to give a striking superficial 

 resemblance to certain Central American specimens of B. squarrosa H. B. K. 

 The achenes surpass those of nearly all other species in the amount of twisting. 

 The twisting commences early, in the young achene, and the mature achenes 

 are frequently twisted through four or five complete revolutions. 



GRACILIS 



- 



1 841; Campylotheca gracilis Walp., Rept. Bot. Syst. 2:618. li 

 No described species of Bidens has been left heretofore in g 

 obscurity than B. gracilis. From the time of Nuttall's 01 

 description, no botanist appears to have given it serious attention. 

 In 1843 Walper categorically transferred the species, along with 

 two others described by 'Nuttall, to Campylotheca. In 1862 

 Gray (Proc. Amer. Acad. 5:128) referred it, along with Bidens 

 mutica Nutt., to B. sandiicensis Less. Nuttall's types of B. 



rva 



(Herb. Brit. Mus.). The type of B. gracilis is clearly distinct 

 that of B. mutica. It is distinct also from the specimens that 

 I assume to be of the type collection of B. sandvicensis Less, by 



from 



Petropol 



Kew 



HlLLE BRAND 



