WiEGAND : Some Species of Bidexs 403 



I. BiDENS bidentoides (Nutt.) Britton, Bull. Torr. Bot. Club, 20 : 



281, 1893 



Diodonia bidentoides Nutt. Trans. Am. Phil. Soc. 11. 7 : 361. 



1841 



Qoreop 



184 



0-8 



short and spreading : leaves pale, undivided, lanceolate to linear- 

 lanceolate (blade 6-10 cm.), on more or less margined petioles 

 (2-5 cm.), regularly tapering to the acuminate apex, coarsely and 

 distantly serrate-dentate, attenuate at the base, upper leaves 

 shorter and on more margined petioles : heads on rather slender 

 peduncles which are mostly shorter than the leaves, longer than 

 broad (15-18 x 10-12 mm.), stramineous; outer involucral bracts 

 4-5, linear or linear-spatulate, 1-3 times the length of the disk, 

 not cihate, entire, erect; inner bracts 5, oblong-Hnear, barely acute 

 (15 mm.) and with the chaff much longer than the flowers : ray 

 flowers rarely present, ligulc strap-shaped, not exceeding the 

 head : the ovaries similar to those of the disk : corolla of the disk 



flowers pale-yellow, large (5 mm. long, y^ length of awns), 



funnelform, 4-toothed, basal portion equaling the upper : stamens 

 rarely exserted : mature achenes very slender, linear-cuneate, convex 

 (8-10 mm.), dark-brown, not papillose, hairy, margins upwardly 

 hairy : awns 2 (rarely a third very short one) very slender and nearly 

 as long as the achene, upwardly barbed. 



Muddy shores of the Delaware River and Bay, Pennsylvania 



to Maryland. 



Specimens examined from : 



Du 



7'and. New Jersey : Camden, Parker, Diffenhach ; Salem, Covi- 

 mons. Delaware: New Castle, Canby ; Wilmington, Canby, 

 Commons (with rays). Maryland : Bush River, Canby. 



Of all the species of Bidens within our limits this is the most 

 hmited in distribution. It is, so far as known, confined entirely to 

 the shores of the Delaware River and Bay, where it may be found 

 growing in the mud at tide-water. The species is very constant in 

 its characters as well as very unique, and must be considered as 

 representing a line of development by itself. With B. discoidea it 

 agrees only in having upwardly barbed awns and hairy achenes, 

 but is remarkably distinct in the form of the achene and In the 



corolla. 



contrary 



comosa. Its affinity seems not to be with any of the species dis- 



