Dec., 1900] 
Tyler — Geophilous Plants. 
21 
GEOPHILOUS PLANTS OF OHIO. 
F. J. Tyler. 
Geophilous — meaning earth loving — is a term which has recently 
been applied to such plants as have some special adaption, which 
enables them to withdraw beneath the surface of the ground when 
adverse conditions, such as extreme heat and drouth, cold, etc,, 
overtake them. Such adaptions may be classified as 
Rhizomes, 
Bulbs, 
Corms, 
Crowns. 
Rhizomes are underground stems and like other stems may be 
simple or branched. The branched rhizome is, however, the most 
common form since it combines vegetative reproduction with the 
other advantages of a rhizome habit. The Brake Fern (Pteris aqui- 
lina L.) is an example of a much branched rhizome and Solomon’s 
Seal (Polygonatum biflorum Ell.) of a nearly simple rhizome. 
The stem of a rhizomatous plant may remain permanently 
underground, as is the case with all ferns except the tree ferns of the 
tropics. An annual stem is, however, usually sent to the surface 
and this may be a lateral branch from the main subterranean stem 
or it may be a continuation of the rhizome, in which case the next 
year’s rhizome will be a lateral branch and thus the whole rhizome 
will be made up of a number of distinct segments. Various members 
of the Iris group are good examples of this. In at least one genus of 
Ohio plants— Sinilax— there are some members having both a per- 
ennial woody stem and a well developed rhizome. It may be that 
these plants are leaving the rhizome habit and are taking up the 
woody stem habit. 
Perhaps in most cases rhizome plants became such through the 
gradual covering of trailing stems. It is a protection and a saving 
of building material to a plant if its stems are trailing or creeping, 
still more so if they are covered by leaf mould or soil. If rhizome 
plants were once trailers there should be every gradation between 
the two and so we find. The Trailing Wahoo is a good example of 
this, since some of its stems are often covered by leaf mould or soil 
while others are on the surface or some inches above. Many of the 
Ericacea? are in this transition stage between trailers and geophytes. 
The Wintergreen (Gaultheria proeumbens L.) has a long, creeping 
stem which is often or usually covered by leaf mould. It roots 
freely and sends up perennial woody branches to the surface. It is 
hard to say in such cases whether the plant is geophilous or not. 
