esent SSE Sat 
nals 
y 
1915] Fernald & St. John,— Species and Varieties of Bidens 25 
IsLAND: sandy pond-margins, east of Dickens Point, Block Island, 
September 15, 1913, Fernald, Long & Torrey, no. 10,688 (TYPE in Gray 
Herbarium). 
Bidens cernua L. as it occurs in eastern America is highly variable 
and especially so in its foliage. Besides the typical form of the species 
with elongate-lanceolate or linear-lanceolate leaves with many coarse 
serrations, we get the dwarf bog plant, var. minima (Huds.) DC., 
with tiny, spatulate or oblanceolate petioled leaves and usually solitary 
campanulate heads; and the very large varieties with broader copi- 
ously serrate leaves, varieties elliptica and integra of Wiegand. On 
the brackish sands of the Magdalen Islands and Prince Edward Island 
occurs a depressed or matted, freely branching plant with the heads 
and achenes and the hispid stems of B. cernua. The small, fleshy 
leaves, however, are mostly obtuse and with few and obscure denta- 
tions, and the outer fleshy bracts of the involucre are oblong or broadly 
oblanceolate and much exceeding the inner series. This little plant, 
though first noted in.maritime sands, does not seem to be restricted 
to brackish habitats, for identical material has been collected on the 
sandy shore of a pond in Coós County, New Hampshire, and an old 
specimen of Gray's from western New York is probably not separable. 
This extreme variation may be called 
B. cERNUA L., var. oligodonta, n. var., humilis plus minusve depressa 
ramosissima 0.5-2 dm. alta; caulibus glabris vel sparse hispidis; 
foliis crassis rhomboideis vel elliptico-oblanceolatis obtusis ad basim 
angustatis subintegris vel pauce dentatis, dentibus utrinque 1-5 
obtusis, foliis primariis 2-5 cm. longis 0.5-1.5 em. latis; capitulis 
hemisphaericis 0.5-1 cm. latis; bracteis foliaceis oblongis vel late 
oblanceolatis obtusis plerumque 1.5-2 cm. longis.— QUEBEC: peaty 
margin of a brackish pond southwest of Étang du Nord wharf, Grind- 
stone Island, Magdalen Islands, August 22, 1912, Fernald, Long & 
St. John, no. 8208 (TYPE in Gray Herbarium). PRINCE EDWARD 
IsLAND: wet brackish sand, North Lake, Kings County, August 24, 
1912, Fernald, Long & St. John, no. 8209. New HAMPSHIRE: 
sandy shore, Success Pond, Coös County, August 27, 1907, A. S. 
Pease, no. 10,738. New York: western section, Gray. 
