54 Henderson — Comparative Study of Pyrolaceae and 



by septate hyphae which appear as balled-together masses in 

 the epidermal cells. All cells and all roots are not equally 

 infested — some roots show no trace of hyphae; others show a 

 few epidermal cells with two or three hyphal threads; others 

 show some epidermal cells packed full of masses of hyphae 

 and a hypertrophied nucleus, and cells in the same root with 

 normal nucleus and cytoplasm. Rommel (65) states that there 

 are no hyphae present in the roots of C. umbellata and that root 

 hairs are present. The writer has examined material from 

 many localities, and has found some roots of each plant infested 

 with hyphae and has never found any traces of root hairs. 

 Beneath the epidermis are one to two layers of elongated cor- 

 tical cells crowded with typical aggregate starch grains com- 

 posed of two to six simple grains, each with a distinct hilum. 

 These appear in safranin-stained sections as hyaline grains with 

 red staining hila. In the same or neighboring cells these grains 

 appear slightly yellowish, but still with a distinct hilum, then 

 yellowish brown with no hilum apparent; and finally the indi- 

 vidual grains merge together to form a sac of brownish material. 

 The secondary roots are produced endogenously. 



The root tip of C. maculata has much the same appearance 

 as that of C. umbellata, except that the epidermal cells of the 

 former beneath the root cap are longer compared with their 

 radial width; these above the root cap are larger in comparison 

 with the other cells than are those in C. umbellata, are more 

 often, and, to a greater extent, infested with hyphae (Fig. 2, 1); 

 and also in those cells not filled with hyphae there appear one 

 to three large bladders, the walls of which are light yellowish 

 in color. These may be the remains of the nuclear membrane 

 after the nucleus has been completely destroyed by the fungus, 

 or enlargements formed by the hyphae similar to those described 

 by Groom (28) in the mediocortex of the absorbing organ of 

 Thismia aseroe and by Gallaud (22) in the roots of Colchicum 

 autumnale. The writer however did not find any hyphae 

 attached to these bladders. 



In Pyrola rotundifolia (Fig. 1, 2) the root cap is strongly 

 reduced, there being only one to two layers of cells. The aspect 

 of the cells at the tip, under the root cap region, is much the 

 same as in the two species just described; but above the root 

 cap the epidermal cells swell out enormously, much more than 



