446 



incompletely developed organs affected ckiring their elongation, rupture and 

 crumble. This is the beginning of the funnel-like depression at the tip of 

 the intumescence. 



Among fruit intumescences, I have most frequently observed the unripe 

 pods of beans and peas and noticed that many varieties of fungi infested 

 the pods. The fruits, especially v\'hen near the surface of the soil, seemed 

 closely covered with warts and awakened the suspicion of a marked fungous 

 infection, as may be seen in the pea-pod shown in Fig. 85. 



In cross-section, it may be seen in different places, which still seem 

 smooth to the naked eye, that some epidermal cells have already begun to 



elongate. These often lie directly beside the 

 stomata, but without the cooperation of the 

 str)mata in jjroducing intumescences. Gradu- 

 ally the [)arenchyma cells lying below be- 

 come elongated. The elongated elements are 

 often divided by cross-walls and form warts. 

 However, these are first formed of rows of 

 cells arranged like columns. These warts 

 grow to a height of one millimeter ; later they 

 become brown from the dying of the peri- 

 pheral layers and, after the covering splits, 

 the rows of cells spread out like a sheaf. 



Fig. 86 shows the greatest development. 

 The normal wall of the pod is shown at fr; 

 e indicates the epidermis ; p layers of the 

 thick-walled partially intersecting elements 

 of the inner parchment-like fruit membrane. 

 In the centre of the outgrowth (w) the 

 elongated columnarly arranged parenchyma 

 cells, separating toward the outside, irregu- 

 larly like a fan, are visible. The outermost 

 peripheral zones, shaded in the drawing 

 [z, z). indicate the moribund tissue. The 

 walls of these collapsed parenchyma groups, 

 often shrinking together in curling tips, seem 

 yellf)w to brown and give the warts an earthy color. bVom the repeated 

 splitting of the intumescences, which are often so close to one another that 

 only a few normal epidermal cells separate them, the whole wall of the pod 

 obtains in places a mossy outer surface. 



The parchment-like inner wall of the pod forms intumescences ; indeed 

 this is more frequently the case than on the outer wall. In some kinds of 

 peas, with very pithy pods, white tissue felts resembling species of mold 

 may be found almost every year on the firm, smooth inner surface. In one 

 case in the intumescence tissue, I found numerous oospores which presum- 

 ably had belonged to Peronospora Viciac. 



Fig. 85. ]'f"a-i)0(ls with glaiui 



like raised outer surface. 



(Orig.) 



