1698 



A TEXTBOOK OF THEORETICAL BOTANY 



becomes spurred. The flowers are hermaphrodite, or rarely polygamous. 

 Cleistogamic flowers are often produced in Viola and produce a greater 

 amount of seed than the open flowers normally do. 



The perianth (Fig. 1562) consists of five persistent sepals and five 

 petals, which may be of unequal size, in which case the anterior becomes 

 larger. 



Fig. 1562. — Floral diagram of Viola. Violaceae. 



The androecium consists of five stamens which are hypogynous. 

 The anthers are erect and converge to form a ring around the style. These 

 anthers are introrse with longitudinal openings and apical appendages. 

 The two anterior stamens are often spurred at the base. 



The gynoecium is unilocular, composed of three to five carpels, and 

 the ovules are arranged on parietal placentas. These ovules are numerous 

 and anatropous. The style is short and the stigma is often hooded. 



The fruit is a capsule, splitting elastically and loculicidally into three 

 boat-shaped valves. These on drying close along the mid-line and in so 

 doing eject the smooth seeds with considerable force, sufficient to throw 

 them several yards. In Hymenanthera and a few other genera the fruit is 

 a berry. 



The seed is small, the testa being hard and shiny. Many species have 

 an oil body or elaiosome on the seed, which attracts ants, and myreme- 

 cochory is characteristic. In climbing genera, such as Agatea, which is 

 found in New Caledonia and Fiji, and Anchieta, native of tropical South 

 America, the seeds are winged. 



Cleistogamic flowers are commonly produced in the genus Viola 

 (see p. 1356) and others. These cleistogamic flowers have been subject to 

 considerable study and are worthy of some reference. In species such as 

 V. canina, F. odorata and V. syhestris, which produce flowers early in the 



