1921] Ames, — Notes on New England Orchids, — I. Spiranthes 81 



broadly cuneate. Gynostemium green, glandular-pubescent on the 

 inner face below the large, broadly ovate, somewhat protuberant 

 stigma, 4 mm. long, the teeth of the rostellum linear-triangular, 

 about 1.5 mm. long. Pollinia as in <S. cernua, Tetrads character- 

 istically irregular, extine pitted reticulate. 



Massachusetts, Bristol County, at border of blueberry swamp 

 on the side of a sloping grassy knoll in run-out pasture. Three 

 specimens found near Wilbor Pond, North Easton, September 11, 

 1920, Ames (Herb. no. 17,391). 



When collected the flowers on the lower half of the raceme were 

 withered, although Spiranthes cernua close at hand had not yet 

 opened any flowers. 



The elongated, slender raceme, the wide-spreading lateral sepals, 

 and the form of the labellum seem to indicate that the specimens 

 here described are clearly referable to S. cernua x gracilis. The base 

 of the lip in the hybrid is more like S. gracilis than S. cernua. An- 

 other bit of weighty evidence is found in the rarity of the plant and 

 its distribution. No other specimens were found although a diligent 

 search was carried on in surrounding fields during the remaining 

 flowering period cf our native species of Spiranthes. 



In my remarks above on S. vemalis I have suggested that our New- 

 England plant referred to it may simply be a hybrid between S. 

 ccrnua and 8. gracilis. If this assumption is correct, then it would 

 seem that the hybrid described under the name Spiranthes X inter- 

 media and recorded as a cross between S. vemalis and S. gracilis 

 may be one of the variants of a cross between S. cernua and S. gracilis 

 in which the characters of S. gracilis are clearly predominant. 



The abundance of fertile seeds produced by our species of Spir- 

 anthes indicates a high degree of successful pollination. I have sus- 

 pected that thrips play an important part in pollinating S. cernua 

 as my observations have been poorly rewarded when I have attempted 

 to detect other insects actually engaged in visits to the flowers. 

 Bombus pennsylvanicus De Geer, with pollinia of Spiranthes cernua 

 var. ochroleuca attached to it, has come into my possession and un- 

 doubtedly other species of the genus Bombus visit Spiranthes flowers 

 for concealed nectar. Dai win observed humble-bees as visitors to 

 Spiranthes autumnalis Rich., and as species of Bombus are reported 

 as the pollinating agents of species of the nearly related genus Good- 

 yera it is safe to classify this group as characterized by humble-bee 



