24 INTRODUCTION 
y. Agamonoecism. Flowers hermaphrodite and neuter: Viburnum Opulus. 
5. Monoecism or Androgyny proper (Linnaeus). Flowers male and female: 
Cucurbita Pepo. 
(4) Trimonoecism. The flowers of the same individual are of three kinds. 
Monoecious polygamy (Darwin). Flowers hermaphrodite, male, and female: 
Saponaria ocymoides. 
II. PLEOMORPHOUS INDIVIDUALS. There are different kinds of stocks 
distinguished by their flowers. 
A. Heteromesogamy. The individuals differ from one another in the 
arrangements for the pollination of their flowers. 
(2) Auto-allogamy. Some individuals of a species are adapted for Autogamy: 
others for Allogamy: Viola tricolor. 
(6) Homo-dichogamy (Errera and Gevaert). Some individuals are homoga- 
mous; others are dichogamous: Ajuga reptans. 
(c) Anemo-entomophily. Some individuals are adapted for insect-pollina- 
tion ; others for wind-pollination: Plantago media. 
(2) Di-entomophily. One group of individuals is adapted for a definite 
class of insects; another group for a different class: Iris Pseudacorus, 
Primula farinosa. 
B. Heterostyly (Hildebrand). The individuals are distinguished from one 
another by the remote position of the sexual organs; the union of two individuals of 
dissimilar form is necessary for complete fertility. 
(az) Heterodistyly. With two kinds of individual, some with long style 
others with short: Primula elatior. 
(2) Heterotristyly. With three kinds of individual, some flowers with long 
style, others with medium, others with short: Lythrum Salicaria, 
C. Hetero-dichogamy. The individuals differ from one another in point 
of time, as regards the sequence of the ripening of their sexual organs: Juglans regia. 
D. Polyoecism. The individuals differ from one another in sex. 
(2) Dioecism. The individuals are of two kinds. 
a. Androdioecism (Darwin). In some individuals hermaphrodite flowers; in 
others male: Dryas octopetala. 
B. Gynodtoectsm (Darwin). In some individuals hermaphrodite flowers; in 
others female: Thymus Serpyllum. 
y. Dioecism proper (Linnaeus). In some individuals male flowers; in others 
female: Salix caprea. 
(4) Trioecism or Trioecious polygamy (Darwin). Some individuals 
hermaphrodite, others male, and still others female: Fraxinus excelsior. 
Through the investigations of Warming, Ludwig, Kirchner, Schulz, and Loew 
this arrangement was subsequently altered and extended to some extent. 
The means by which flowers attract insects were studied by Grant Allen, and 
afterwards in a very exhaustive way by Hermann Miiller (‘Alpenblumen’). The 
