MODES OF POLLINATION AND DISTRIBUTION OF SEXES 29 
A. ALL FLOWERS ARE UNISEXUAL: Dicliny (Division of sexes). Only Allogamy 
possible. 
1. Male and female flowers on the same plant: Monoecism (Linnaeus) or 
One-house plan. Geitonogamy and Xenogamy are possible. 
2. Male and female flowers on different plants: Dioecism (Linnaeus) or 
Two-house plan. Only Xenogamy is possible. 
B. ALL FLOWERS ARE HERMAPHRODITE: Monocliny (Linnaeus) or Bi-sexuality. 
1. The stigmas and anthers of the same flower are not simultaneously mature : 
Dichogamy (Sprengel). If this peculiarity is so well marked that the stigmas 
have dried when the anthers spring up, or vice versa, only Cross-pollination is 
possible. If it is not so well marked, Self-pollination is possible later on. Dichogamy 
appears in two forms :— 
‘(a) The anthers are ripe before the stigmas have developed: proterandry 
(Delpino) or profandry (Hildebrand). 
(6) The stigmas are ready to receive pollen “before the anthers dehisce : 
proterogyny (Delpino)', profogyny (Hildebrand). 
2. The stigmas and anthers of a flower are simultaneously mature: Homogamy 
(Sprengel). 
a. The flowers are open at the time of the maturity of stigma and anthers: 
Chasmogamy (Axell). 
a. Spontaneous self-pollination is impossible in consequence of the relative 
positions of stigma and anthers: Herkogamy (Axell). 
8. Spontaneous self-pollination is rendered possible by the relative positions 
of stigma and anthers: 
(a) All flowers are similarly constructed as regards length of style and 
stamens: Homomorphy or Homostyly (Hildebrand). 
(8) On different plants there are flowers distinguished by a difference in 
length of stamens and style: Heferomorphy. 
* The styles and also the stamens are of different lengths: Heferostyly 
(Hildebrand). 
+ Two different forms of flowers occur: some with long styles and 
short stamens, others with short styles and long stamens: Dz- 
morphism (or better, Heferodzstyly). 
++ Three different forms of flowers occur: some with long styles and 
medium and short stamens, others with medium styles and long 
and short stamens, others with short styles and long and medium 
stamens: Zrimorphism (or better, Heterotristyly). 
** Only the stamens are of different lengths :. He/eranthery. . 
b. The flowers are closed at the time of maturity of stigma and anthers: 
Cleistogamy (Kuhn). 
1 Delpino distinguishes (1) Proterogynia brachybiostigmata, that is Proterogyny with short- 
lived stigmas, if the stigmas fade before the anthers burst so that self-pollination is prevented, and 
(2) Pr. macrobiostigmata (Pr. with persistent stigmas) when the stigmas remain capable of receiving 
pollen till the anthers are ripe, so that self-pollination is at least possible. 
