BICKNELL: FERNS AND FLOWERING PLANTS OF NANTUCKET 613 
the submerged plant and of a distinctly different form, depressed- 
subglobose and wider than long instead of broadly obovoid and 
longer than wide; actual measurements were 2 mm. wide by 
I mm. long in the terrestrial plant and only I-1.5 mm. wide by 
I mm. long or more in the normal aquatic form. : 
CISTACEAE 
CROCANTHEMUM CANADENSE (L.) Britton. 
Helianthemum canadense Michx. 
The typical plant is not common and is rather local in its 
distribution, giving place to the following, which is everywhere 
abundant. It is however frequent in the oak barrens towards 
Siasconset and is found sparingly in Quaise, on the plains towards 
the south shore, on Great Neck and elsewhere. No flower buds 
visible June 3, 1909; first flowers June 11, 1909; in full flower 
June 19, 1910; a few flowers remaining June 30, 1912. Reduced 
petaliferous flowers are often produced in September. 
*Crccanthemum dumosum sp. nov. 
Similar to Crocanthemum canadense but lower and of more 
branched and spreading habit, commonly diffuse and semi- 
prostrate or ascending, the pubescence somewhat more densely 
and softly canescent, intermixed with scattered non-stellate 
longer hairs and some minute glandular hairs of a reddish color; 
leaves smaller and shorter than those of C. canadense and of a 
more bluish green color, mostly oval and elliptic and obtuse, 
often very small and crowded on the short divergent branchlets; 
flowers slightly paler than in C. canadense; mature calyx 
often larger, the sepals very broad and mostly acuminate, usually 
bearing reddish papillae on the outer surface and reddened glandu- 
lar or viscid hairs in the pubescence; primary inflorescence an 
ascending succession of single petaliferous flowers succeeded by 
rather numerous flowers intermediate in size and character be- 
tween these and the later apetalous ones. 
Well marked and abundant all over Nantucket, combining 
with such common and characteristic island plants as Amelanchier 
nantucketense, Ilex fastigiata, and Linum intercursum to stamp the 
flora with a signally distinctive character. It is found also on 
Marthas Vineyard and on the Hempstead Plains of Long Island. 
