THE GOUKD FAMILY. 253 



described by Miiller ? ^ Does their structure indicate self- 

 or cross-fertilization ? 



V. Examine the ovary of one of the oldest flowers. 

 Is there any external indication of the number of carpels ? 



Make a transverse section and notice the number of 

 cells, the position of the placentae, and the form and direc- 

 tion of the ovules. Draw the section in outline. Repre- 

 sent by dotted lines the commissural lines of union of the 

 carpellary leaves.^ 



RELATIONSHIP. 



Seeds of squash, melon, and many other plants belonging 

 to this family, are easily procurable, and afford the means 

 of extended and instructive comparative study. Seedlings, 

 which may be had in the course of a few days, exhibit 

 with remarkable uniformity in the different genera the 

 characteristic contrivance by which the seed-coats are 

 ruptured and the cotyledons released.^ Tendrils of vari- 

 ous species, that may be studied anywhere a little later 

 in the season, are of the greatest interest, morphologically 

 as well as physiologically, and in their turn contribute to 

 the sum of characteristic features by which this family is 

 marked. If all these are carefully studied, as well as the 

 flowers and fruits, and due weight is given to every well- 

 marked trait, it will be found that the " family characters" 

 include more than the structural details usually given. 

 The behavior of the seedlings in breaking through the' 

 ground, the highly developed tendrils and their mode of 

 action, and even the active properties of some of the 



1 Fertilization of Flowers, pp. 268, 269. 



2 Cf. Eiohler, Bluihendiagramme, p. 306. 



* Darwin, Power of Movement in Plants, p. 102. 



