1907] Bartlett, — Retrograde Color Varieties of Gratiola aurea 123 
Two published references to these forms have been found, the earlier 
of them, in John Robinson's **Flora of Essex County, Massachusetts," 
to the effect that “There is a white variety of this species which grows 
in Bowler Swamp, Lynn," the other, in Dame and Collins's ‘Flora of 
Middlesex County, Massachusetts," to the effect that ‘‘The white 
variety has been found at Winchester by W. H. Manning; both the 
white and light yellow varieties at Westfield, by Dr. Swan." In the 
Gray Herbarium there is a sheet of specimens collected by Dr. Swan 
in a swamp near Lowell, Mass., on which is written, in Dr. Gray's 
hand,— “Gratiola aurea vars. Ordinary golden-yellow. Pale yellow! 
White-flowered! in small quantity." 
The two forms, as observed at Winter Pond, are absolutely distinct, 
without intermediates linking them either to the parent form or to 
each other. They occur in pure colonies, several of which have been 
under observation for three years, during which time they have been 
visited at various dates between July Ist and Sept. 15th, an interval 
which practically covers the flowering period of the species. Never 
has the honey-colored form been found in a white colony, nor vice 
versa, although this might be expected to happen occasionally through 
the casualties of seed dispersal. 
The forms may be named: Gratiola aurea f. helveola f. nov. a forma 
typica recedit floribus albogilvis, corollae limbo quam tubo pallidiore. 
— Type (in Herb. Gray) collected by Dr. C. W. Swan at a swamp 
near Lowell, Mass. Gratiola aurea f. leucantha f. nov. a forma typica 
floribus clare albis differt.— Type (in Herb. Gray) Bartlett 820, Winter 
Pond, Winchester, Mass., 7 July 1907. 
'The significance of these forms (retrograde varieties of de Vries) 
as throwing light upon the origin of specific distinctions is clear at 
once when the flower-color of the other American species of $ Gratio- 
laria is examined. (The often purple-flowered $ Sophronanthe may 
be left out of consideration on the ground of its great habital diversity.) 
We find: I) Species with golden-yellow flowers, — G. aurea Muhl., 
G. Torreyi Small and G. pusilla Torr. II) Species with flowers 
merely yellowish, the limb often white or whitish,—G. gracilis Benth., 
G. floridana Nutt., G. virginiana L., G. viscosa Schwein., G. Drum- 
mondii Benth. G. ramosa Walt. and G. ebracteata Benth. III) Species 
with white flowers, — G. sphaerocarpa Ell. and G.macrantha Chapm. 
F. helveola corresponds to the second section in the.above grouping, 
f. leucantha to the third. The golden-yellow color of the first group 
