a Dae: Te 
PART 1. | HISTORICAL INTRODUCTION. 9 
The final result of these researches, which were marked by all 
his usual care and patience, may be summed up in the following 
statements :— 
In dimorphic heterostyled plants (species of Primula, Pul- 
monaria, Linum, etc.) two forms exist, in fairly equal numbers 
and growing for the most part near together; while in other 
respects completely or almost completely alike, they differ from 
one another in this particular, that in the flowers of the one 
form the anthers stand distinctly above the stigma, while in the 
other form the positions are reversed; further, that in each form 
the anthers stand at the same level as the stigma in the other ; 
and finally, that in the long-styled form the stigma is rough and 
1-10, Primula elatior. 1—5, long-styled flower; 6—10, short-styled flower ; 2, 7, pollen-grains, 
dry ; 3, 8, ditto, moist; 4. 9, stigma; 5, 10, stigmatic papille. 
11—18, Pulmonaria officinalis. 11, long-styled flower in section ; 12, pollen-grains of ditto, dry ; 
18, ditto, moist ; 14, short-styled flower; 15, pollen-grains of ditto, dry; 16, ditto, moist; 17, 18, 
stigma and stigmatic papille common to both forms. 
furnished with long papille and the polien-grains are small, while 
in the short-styled form the stigmatic papille are short and 
close-set and the stigma seems smooth and the pollen-grains are 
larger. In trimorphic heterostyled plants (Lythrum salicaria) there 
exist three forms, one with long-styled, one with mid-styled, and 
one with short-styled flowers ; and in each form there are two 
whorls of stamens whose anthers stand respectively at the same 
height as the stigmas in the other two forms; the tallest stamens 
produce the largest pollen-grains, and the shortest produce the 
smallest, 
