100 



SEEDS AND SEEDLINGS 



juxtaposition with the hilum, as we saw in the bean. How 

 does this differ from the anatropous kind ? Compare the 

 seed you have examined and the drawings you have made 

 with Figures 224-227, and see if you can tell to which 

 class each belongs. Why are these distinctions not appli- 

 cable to corn and other grains ? (Sec. 91). 



132. Position in the Pericarp. — The terms "orthotro- 

 pous," "anatropous," etc., refer to the position of the seed 

 on its footstalk and have nothing to do with its attachment 



229 230 



228-230. — Position of seeds in the carpels : 228, erect seed of Ceanothus ; 229, 

 horizontal anatropous seeds of the European star-of-Bethlehem ; 230, suspended 

 seeds of Polygala. 



to the pericarp, which may be either erect, horizontal, or 

 suspended. An orthotropous seed may hang bottom up- 

 wards from the apex of the carpel without altering its 

 character ; and in Uke manner one of the anatropous kind 

 may be attached in such a way as to bring it back, by a 

 double inversion, to the upright position. The castor bean 

 furnishes a good example of this. 



133. Seed Dispersal. — This subject has already been 

 touched upon in the chapter on fruits, and the object of 

 distribution is in both cases the same. The agencies of 

 dispersal are either natural, i.e. by wind, water, and animals, 

 or artificial, that is, by man. 



134. Wind Dispersal. — A common example of wind dis- 

 persal is afforded by the class of plants known to farmers 

 as " tumble weeds." Well-known examples of these are the 

 Russian thistle, winged pigweed, "old witch grass," hair 



