GROSS ANATOMY OF FLOWERING PLANTS. XXXVU 



* 



Examples of dimorphous flowers are common in many genera 

 of plants; e.g., in Bluets (Houstonia), Partridge Berry (Mitchella), 

 Primrose (Primula), Puccoon (Lithospermum), Buckwheat (Pago- 

 pyrum), etc. etc. (Pigs. 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 (Pig. XXXVIII). 



§ 6. The Fruit. 



Structure. — The -fruit may include (1) only the ripened ovary 

 (pericarp) with its contained seeds — e.g., the bean; or (3) these 

 with an adnate calyx or receptacle — e.g., the apple. 



Fio. XXXIX.— Capsulary fruits: 1, legume; 2, capsule, showing loeulicidal 

 dehiscence; 3, pyxis, showing oircumcissile dehiscence; 4, silique. 



During the ripening, changes in structure may take place, as (1) 

 the growth of wings or prickles; (3) the thickening of the walls 



