172 ELEMENTS OF BOTANY. 
bee which may enter. A little study of Fig. 156 will make 
clear the way in which the anthers are hinged, so that a bee 
striking the empty or barren anther-lobes a knocks the pollen- 
Fie. 156.— Flower and Stamens of Common Sage. 
A, p, stigma; a, anthers. B, the twostamens in ordinary position ; /f, filaments ; 
m, connective (joining anther-cells); a. a’, anther-cells. C, the anthers and 
connectives bent into a horizontal position by an insect pushing against a. 
bearing lobes a! into a horizontal position, so that they will 
he closely pressed against either side of its abdomen. 
Fig. 157.— Dimorphous Flowers of the Primrose. 
I, I, short-styled form ; III, IV, long-styled form, natural size; a, throat of 
the corolla; S,s, stamens; G, g, styles. 
210. Flowers with Stamens and Pistils each of Two Lengths. 
—The flowers of bluets, partridge-berry, the primroses and 
a few other common plants secure cross-fertilization by hay- 
