68 



ANGIOSPERMAE—DICOTYLEDONES 



pp. 225-7; Ixiii, 1895, pp. 97-8; F. E. Weiss, New Phytol., London,^ii, 1903, p. 99, 

 iii, 1904, p. 168.) — This species bears heterostylous flowers belonging to class HhL. 

 Those examined by me in Schleswig-Holstein were of sulphur-yellow colour, with a 



Fig. 241. Primula vulgaris, Huds. 



(1) and (2) Short- anj long-styled flowers, in longitudinal 

 section (X 2). 



3 

 



4 

 



Relative size of the pollen-grains 

 (3) of the short-styled, and (4) of the long-styled (lower. 



Relative size of the stigmatic papillae 

 (5) of the long-styled, and (6) of the short-styled flower. 



darker nectar-guide at the base of each corolla-lobe. Their diameter varied from al- 

 to 4 cm., but was usually about 3 cm. Similarly the length of the corolla- tube 

 was i|-2§ cm., mostly, however, about 2 cm. 



In the long-styled form the stigma is situated in the opening of the flower, 

 while the anthers are inserted into the corolla-tube about its middle. In the 

 short-styled form the opening of the corolla-tube, which widens somewhat like 

 a funnel, is, of course, occupied by the five anthers, while the style with its stigma 

 is about half as long as the tube. There are microscopic differences between 

 the two forms as regards the length of the anthers and the shape of the stigma. 

 In short-styled flowers the anthers are generally rather more than 2 mm. long, 

 in long-styled ones usually a little less. The stigma in the latter is spheroidal 

 as a rule with a diameter of i-i mm., but in short-styled flowers it is mosdy 

 somewhat flattened, about 1-2 mm. broad and 0^9 mm. deep. With the aid of 

 a lens the stigmatic papillae of the long-styled form are clearly visible, but those 

 of the short-styled one scarcely perceptible. The former are 0-07 mm. long and 

 o-oi mm. broad, the latter 0-02 mm. long and about the same in breadth. The 

 pollen-grains are of an angular ovoid shape, those of the long-styled form 0-025 '^'^■ 

 long and 0-02 mm. broad, and those of the short-styled one almost 0-04 mm. long 

 and 0-025 mm. broad. 



As in the case of the last species, Ljungstrom observed four varieties in the 

 island of Moen, i. e. brevicalyx, longicalyx, laliloba, and angustiloha. He also 

 noticed a form [laclea) with an almost milk-white corolla, and another (colorata) 



