Gruenberg : Some aspects of the mycrohiza problem 167 



Monotropa a convenient substratum. Formally, this interpreta- 

 tion explains the relation well enough, but it is not certain that 

 that is all there is to the matter. In several species of Corallorhiza^ 

 the coral-root orchid, chlorophyl is entirely absent, and the leaves 

 are reduced to a few inconspicuous, sheathing scales. Neverthe- 

 less these plants contain large amounts of starch in the under- 

 ground portions as well as some in the scape and in the floral 

 organs. 



We may account for the presence of starch in these plants in 

 the same way as we account for it in the underground portions 

 of a green plant, that is, we may say that it has been condensed 

 from sugar. The real problem in the coral-roots is, how do they 

 get their sugar? Many authors have described these plants and 

 others without chlorophyl as having no stomata ; this may have 

 been due X.o faulty observation, or to a priori reasoning from the 

 absence of chlorophyl, or to biased observation. The fact re- 

 mains that in all species of Corallorhiza examined by the writer, 

 stomata are well developed in all parts of the plant, including 

 floral envelope and rhizome. On the latter, the stomata are fre- ^ 

 quently clogged with earth, but there is no doubt as to their pres- 

 ence. The absence of all absorbing organs has also been declared 

 to be characteristic of these plants. But there is present on each 

 internode of the rhizome a whorl of tiny papillae which are found 

 to bear tufts of fine hairs that may well serve as root-hairs in the 

 absorption of soil water. These trichomes are very delicate and 

 easily destroyed in removing the rhizome from the adhering soil, 

 but they may be easily found by washing the soil off in several 



changes of water. 



Now, the plant having been provided with stomata and absorbing 

 organs, it may be supposed that the organism is prepared to manu- 

 facture its carbohydrates in the orthodox fashion, since it has some 

 chVomoplasts in the parts above ground. But the area exposed 

 to the light is very small, in comparison with the bulk of the sub- 

 terranean portion, and the absorbing surface is also very small. 

 Still these facts could not be taken in themselves to preclude the 

 possibility of photosynthesis. A vigorous specimen of Corallorhifza 

 iniiltiflora growing in a pine grove was examined for starch by 

 scraping off the skin at several points and treating with dilute 



