WALDRON— THE PEANUT 319 



Stripped off, which is a very unique event in fruit maturation. Ap- 

 parently the epidermis does not keep up with the growth from within. 

 Within the epidermis several layers of periderm have already ap- 

 peared, similar to, and continuous with, that of the lower end of the 

 fruit stalk (gynophore). Till this occurs and until the fruit is one 

 half to three quarters full size, no hairs are formed on any part of 

 the ovary or young fruit. About this time, however, and lasting 

 until the fruit is mature, there appear on this layer irregular, often 

 branched, one-celled absorptive hairs (Plate LXXIX, Fig. 6). 



The developing bundles have increased in size, and with their 

 connecting branches, form ridges which later give the reticulations 

 to the fruit. Meantime a few layers, just interior to these, are be- 

 coming remarkably indurated to constitute the solid enclosing 

 chamber of the mature fruit. The inner endocarp area of small 

 cells has enormously thickened and from the time the fruit has be- 

 gun to swell until nearly ripe, this area is composed of very large, 

 thin walled, pith-like cells which contain sugar. This area remains 

 thick and the developing seed small until a short time before maturity. 

 It forms a large part of the fruit at this time. 



Anatomy of the Mature Fruit. Winton notes the presence of an 

 epidermis and states that it is not easily seen. As noted in the dis- 

 cussion of the developing fruit, this could only be a pseudo-epidermis 

 that he has mistaken for the already shed epidermis, and the fact 

 that it is the small-celled third laver of the ovarian tissue mav ex- 

 plain why it is distinguished with difficulty. As in the nearly ma- 

 ture fruit, absorbing hairs are present as wall extensions of it. These 

 hairs were not observed to be as often branched as in the younger 

 fruit. One or two appeared to be septate. 



Just below the outer absorbing layer are several rows of brick 

 shaped, thin walled cells, simulating those of the hypogeal gynophore 

 in appearance and position. Within this are several layers of thin 

 walled cells that have collapsed. Apparently new cells were not 

 produced for this area to allow for the expansion of the fruit. These 

 surrounded a few layers of unbroken, rounded cells in which are em- 

 bedded the branching vascular bundles. Large bundles are arranged 

 longitudinally, and are connected by short smaller cross bundles, 

 the whole system forming the reticulation of the peanut shell. The 

 xylem and phloem of these have become highly lignified. 



Attached to the inner edge of the bundle network is the solid hard 

 enclosing shell of the peanut, composed of the now mature lignified 



