PEEFACB TO THE EEPEINT OF 1884. vu 



xxiv., 1882) states that the Turneracese contain a large 

 proportion of dimorphic plants. His monograph on 

 this family I know only from the abstract in the ' Botan. 

 Gentralblatt,' p. 207. He has made . the following 

 interesting observations : — " In the Turneracese the 

 dimorphic species tend to be perennials^ with con- 

 spicuous flowers, while the monomorphic species have 

 smaller flowers, and are chiefl.y annuals." He states 

 that a tendency to dimorphism in the monomorphic 

 species expresses itself only in elongation of the style. 



In the subjects kindred to those considered in 

 Chapter VII. rather more work has been done. 



F. Ludwig (' Zeitschrift f. d. gesam. Naturwiss,' 

 1879, p. 4A) describes three plant-forms in Plcmtago 

 lanaeolata. 



1. Hermaphrodites with white anthers. 



2. Semi-females, with small shrivelled yellow 

 anthers, containing a small quantity of pollen, of 

 which many grains are bad. 



3. Purely female form. 



Ludwig has noticed the tendency described by 

 Delpino to entomophily in Plantago, the flowers being 

 often fairly conspicuous, and are visited by insects. 



Ludwig draws some interesting general conclusions 

 on G-ynodioecious plants. 



1. They are all more or less dichogamic. 



2. In the protandrous forms the females are more 

 numerous at the beginning of the season. In the 

 protogynous forms the reverse is the case. 



3. Abortive anthers often degrade into perianth 

 segments. 



4. He confirms the received opinion that female 

 flowers are smaller than hermaphrodites. 



He discusses the origin of diceciousness, assigning 



