GROSS ANATOMY OF FLOWERING PLANTS. XXXVI 
Examples of dimorphous flowers are common in many genera 
of plants; e.g., in Bluets (Houstonia), Partridge Berry (Mitchella), 
Primrose (Primula), Puccoon (Lithospermum), Buckwheat (Fago- 
pyrum), etc. ete. (Figs. XXXVI and XXXVII). 
When, as in some species of Oxalis, there are three forms, viz., 
long-, mid-, and short-styled, the term trimorphous (or better 
heterogonous trimorphous) is used (Fig. XX XVIII). 
§6. Tue Fruit. 
Structure.—The fruit may include (1) only the ripened ovary 
(pericarp) with its contained seeds—e.g., the bean; or (2) these 
with an adnate calyx or receptacle—e.g., the apple. 
Fic. XXXIX.—Capsulary fruits: 1, legume; 2, capsule, showing loculicidal 
dehiscence; 3, pyxis, showing circumcissile dehiscence; 4, silique. 
During the ripening, changes in structure may take place, as (1) 
the growth of wings or prickles; (2) the thickening of the walls 
