MIGRATION 45 



case of streams and run-ofE, especially, mobility plays little 

 part, provided the disseminules are impervious, or little 

 subject to injury by water. Motile plants, or those with 

 motile cells, which belong entirely to this group, may be 

 distinguished as autochores {Autochorae, auTo's, self), which 

 correspond closely to mastigospores. 



2. Wind, anemochores (Anemochorae, xveiio^, -wind). This 

 group" includes the majority of all permobile terrestrial 

 plants, i.e. those in which modifications for increasing sur- 

 face have been carried to the extreme, or those which are 

 already permobile by reason of the minuteness of the spore 

 or seed. Saccate, winged, comate, parachute, pappose, 

 plumed, and, to a certain extent, awned seeds and fruits re- 

 present the various types of modifications for wind-distri- 

 bution. 



3. Animals, zoochores {Zoochorae, ^S)ov,t6, animal). Among 

 terrestrial plants, dissemination by attachment represents 

 essentially the same degree of specialisation as is found in 

 wind-distributed plants. The three types of contrivances 

 for this purpose are found in spinose, hooked, and glandular 

 fruits. Dissemination by deglutition and by earrlage, either 

 intentional or unintentional, though of less value, play a 

 striking part on account of the great distance to which the 

 seeds may be carried. Dissemination by deglutition is 

 characteristic of sarcospores, and distribution by carriage 

 of creatospores. 



4. Man, brotochores {Brotochorae, /Sporos, o, a mortal man). 

 Dissemination by man has practically no connection with 

 mobility. It operates through great^^distances and over im- 

 mense areas as well as near at hand. It may be intentional, 

 as in the case of cultivated species, or unintentional, as in 

 thousands of native or exotic species. No other dissemin- 

 ating agent is comparable with man in respect to universal 

 and obvious migration. 



5. Gravity, clitochores {Glitochorae, kXitos, t6, slope). The 

 members of this group are^exclusively colline, montane, and 

 alpine plants, growing on rocks, cliffs, and gravel-slides 

 (talus), etc., in which the seeds reach lower positions merely 



