WALDROX— THE PEANUT 331 



The chlorophyll formed in the fruits exposed to light was found 

 to be exterior to and around the bundles that form the pericarp re- 

 ticulations. The testa and cotyledons also became green. This is 

 an interesting point since it indicates the retention through long 

 millenia of the factors necessary for chlorophyll formation. 



Watt has observed in India that red ants are frequently found 

 working harmlessly around growing fruits in the soil. This would 

 be of benefit to the fruit since aeration of the surrounding soil would 

 allow for greater absorptive hair development. What benefit the 

 ants might obtain is hard to tell. 



Fruit Hairs. It should be kept in mind that the fruit hairs are 

 different in origin from any found elsewhere on the plant (see page 3 19). 

 Points of evidence indicating this are — (i) that the epidermal and 

 subjacent layer of cells is seen to be thrown off (see pagejig and Fig. 

 6). (2) That the hairs are different from any found elsewhere 

 on the plant, all of which are truly epidermal. (3) That this differ- 

 ence, that is the bifurcations of the hairs, indicates the irregularity 

 of growth of the mesophyll of leaves. (4) That no hairs appear on 

 the fruit until it is well grown and the two outer layers have been 

 discarded. 



Other queries raised here are: why is the second layer of cells 

 discarded as well as the epidermis? and why doesn't the periderm- 

 like tissue begin its formation by divisions taking place in this layer, 

 as is the case with the hypogeal gynophore, instead of in a deeper 

 layer? One possible answer is, that this corresponds to that layer 

 of water storage cells next to the lower epidermis of the leaves of 

 Arachis. This layer still persists in the carpel, and, being large- 

 celled and less able to divide, is thrown off with the epidermis. 



Conclusions from Physiological Studies 



It remains to be considered how far the facts ascertained in this 

 study contribute to the knowledge of hypogeal fruit production. 

 The fact that the fruit of so many plants of varied families seeks the 

 ground must be regarded as significant. Tschirch,^^ in a paper on 

 Leguminosae, says that one group of nitrogenous compounds pro- 

 duced by the Leguminosae can be formed only in darkness, and sug- 

 gests this reason for such a habit. It has also been suggested that 

 the fruit is thus protected from animals. 



Concerning the present studies, the following new facts stand 

 out quite prominently — (i) The tendency to fruit formation in 



