THE ANGIOSPERMAE 1269 



THE SEXUAL STATUS OF FLOWERS 



Errera and Gevaert in 1878 drew up the following classification of the 

 distribution of the sex organs in flowers, covering all observed variations. 

 It well illustrates the differences which exist in this respect. The personal 

 names in brackets denote the introducer of the term referred to. 



I. Individual plants, monomorphic, i.e., all alike in regard to the flowers they 

 bear. 



1. Flowers monomorphic. All flowers alike, hermaphrodite. 



2. Flowers heteromorphic. Flowers of two or more kinds on each plant. 



A. Monoecious. Flowers on each plant either male or female. Zea, 

 Ciicurbito. 



B. Dimonoecious. Flowers of two kinds on each plant, herma- 

 phrodite and another kind. 



1. Andromonoecious (Darwin). Flowers hermaphrodite and 

 male. Aescidus. 



2. Gynomonoecious (Darwin). Flowers hermaphrodite and 

 female, Atriplex, Parietaria. 



3. Agamonoecious. Flowers hermaphrodite and sterile. Vibur- 

 num, Centaiirea. 



C. Trimonoecious, or Coenomonoecious (Kirchner), or Monoecious 

 polygamous (Darwin). Flowers hermaphrodite and male and 

 female, on each plant. Acer, Ricinus. 



II. Individual plants, heteromorphic. Two or more kinds of individual, 

 distinguished by their flowers. 



1. Heterostyly (Hildebrand). Flowers on different plants differing in the 

 development of their sexual parts. 



A. Distyly (Dimorphism). Two kinds of individuals, bearing long- 

 styled and short-styled flowers respectively. Primula. 



B. Tristyly (Trimorphism). Three kinds of individuals, bearing long, 

 short and medium-styled flowers respectively. Lythrum. 



2. Polyoecism. Individuals of diflerent sexual status. 



A. Dioecious (Linnaeus). Individual seither wholly male or female; 

 true dioecism. Salix. 



B. Androdioecious (Darwin). Some individuals male, others herma- 

 phrodite. Dryas, Caltha. 



C. Gynodioecious (Darwin). Some individuals female, others 

 hermaphrodite. Thymus. 



D. Trioecious or trioecious polygamous (Darwin). Some individuals 

 male, others female and others hermaphrodite. Fraxinus, 

 Ruscus, 



