62 INTRODUCTION 
Other known cases of parthenogenesis occur among orchids, grasses, and 
Hippeastrum ; on the other hand, according to Bonavia (Gard. Chron., London, viii, 
1890), the development of embryos of Ficus Roxburghii without pollen, as observed 
by Cunningham (loc. cit.) has not been sufficiently proved. 
A. Ernst (‘A new case of Parthenogenesis in the vegetable kingdom’) found 
that in Disciphania Ernstii Z7zch/. (in Caracas) two plants produced an increasing 
number of fruits in three successive years, although the nearest male plants were 
nine miles away from the place of observation, so that there could be no question 
of cross-fertilization ’. 
VII. Flower-Groups. 
As already mentioned on p. 14, Delpino, in his work ‘ Ulteriori osservazioni 
sulla dicogamia nel regno vegetale,’ has arranged the floral mechanisms known to 
him in adaptational groups, and so has established a classification of plants according 
to their mode of fertilization. His scheme, which embraces the whole vegetable 
kingdom, is as follows :— 
A. ZoocamaE: plants with reproductive elements capable of movement. Among 
these are most of the Cryptogams, in which the spermatozoids are motile. 
B. DiamesocaMaE: plants in which the reproductive elements require external 
means of conveyance. 
I. Hydrophilae (Water-pollinated Plants): plants which are pollinated 
by the agency of water. 
(a) Pollination is effected under water: the pollen-grains or the spores possess 
the specific gravity of water: Posidonia, Cymodocea, Zostera, Cerato- 
phyllum, Florideae. 
(4) Pollination is effected on the surface of the water: the pollen is lighter 
than water, or is borne on a float; the stalks of the female flowers grow 
up to the surface of the water: Ruppia, Vallisneria. 
II. Anemophilae (Wind-pollinated Plants): plants which are pollinated 
by the agency of wind. 
(2) Wind-pollinated plants zw/hout stigma: Gymnosperms. 
(2) Wind-pollinated plants zth stigma—this being usually well developed. 
1. Cathkin form (typus amentifiorus): the male inflorescences have long movable 
axes (Corylus, Betula, and so forth). 
2. Form with pendulous flowers (typus penduliflorus): Negundo fraxinifolium, 
Rumex. 
3. Form with long movable filaments (typus longistamineus). This very common 
form of wind-pollinated flower occurs in almost all Gramineae, Cyperaceae, and 
Juncaceae, also in Cannabis, Humulus, Mercurialis, Ricinus, Plantago, Litorella, 
sp. of Callitriche, Myriophyllum, Hippuris, and others. 
4. Form with elastic explosive stamens (typus explodens): Urtica, Parietaria, 
1 [Other cases have been recorded since the publication in 1898 of the German text. A useful 
summary with references to the literature will be found in Coulter and Chamberlain, ‘ Morphology 
of Angiosperms,’ New York, 1903.—ED. ] 
