Some PROBLEMS IN CORALLORHIZA. 
By M. B. THomas. 
Some recent discussions regarding the relation of endophytic mycelium 
to the roots of certain orchids and allied plants has suggested an investi- 
gation into this condition in the Orchidaceae, and the results show that 
out of fifty species of orchids examined all present this relation in a vary- 
ing degree. The very peculiar root system of the plants of this family 
may be accounted for by the influence of this semi-parasitic condition. 
In corallorhiza, no doubt most of the nutrient material taken in is 
through the agency of these very abundant hyphae, while in the cypri- 
pediums, though present, the hyphae do not play a very conspicuous part 
in the absorption of food by the plant. 
The great abundance of the hyphae in certain green orchids leads us 
to infer that the presence of these threads alone is not sufficient 
to account for the very remarkable phenomena in certain colorless orchids 
like corallorhiza, ete. 
In my judgment, other and less obvious changes will yet be determined 
that will assist in accounting for the very remarkable life history of 
corallorhiza. : 
The paper deals with some of the problems along this line and the 
results will be published elsewhere. 
Tue DISAPPEARANCE OF SEDUM TERNATUM. 
By M. B. THOMAS. 
Attention is called to the very unusual condition of a plant in which 
modifications for adaptation to its peculiar environment failed to protect 
it from the severity of the fall and winter of 1898-9. Sedum tenatum 
Michx., a plant found in several localities previous to that time, completely 
disappeared, so that no trace of it remained in the local flora of Craw- 
fordsville. 
The paper, which is to be published in full elsewhere, deals with the 
history of adaptation in this plant. 
10—Science. 
