244 THE STORY OF PLANT LIFE 



The leaves are either opposite or alternate, or in 

 whorls, and usually entire. As a rule there are no 

 stipules. 



The flowers are regular, solitary, in axils of the 

 leaves, or in racemes, spikes or panicles. They are 

 hermaphrodite and zygomorphic as a rule. The parts 

 of the flower are generally in fours, but sometimes 

 either in twos, threes or fives. A characteristic 

 feature is the inferior ovary, the axis being continued 

 above into the calyx-tube. The calyx is gamosepalous, 

 superior, with two to four lobes, and is valvate in bud. 

 The coralla is polypetalous and consists of four or 

 two petals, which are usually twisted in bud. The 

 flowers are apetalous in Ludwigia. The petals are 

 perigynous, fugacious, soon falling. The disc is 

 epigynous, and forms a lining to the calyx-tube. The 

 stamens are two, four or eight, and are perigynous, 

 in one or two series, and are sometimes declinate. 

 The anthers are oblong and the pollen is triangular. 

 The pistil is syncarpous, inferior, and consists of four 

 carpels. The ovary is four- or six-celled. The style 

 is slender, with a knob-like stigma, entire or four- 

 lobed. The fruit is a capsule as a rule, loculicidal, 

 but may be a drupe, nut, or a berry. The seeds are 

 single or numerous, and are practically all exalbu- 

 minous, papillose or hairy. 



The flowers are adapted to bees or butterflies and 

 moths, some, as the Evening Primrose, opening at 

 night. The anthers of most open first. In the exotic 

 Lopezia coronata the flowers are explosive. 



