4io 
The Ohio Naturalist. 
[Vol. Ill, No. 6, 
OHIO PLANTS WITH CONTRACTILE ROOTS. 
One of the interesting phenomena to be observed in studying 
geophilous plants is the habit which some have of keeping certain 
parts of their body below the surface by means of contractile roots. 
This subject has received the attention of DeVries, Rimbach and 
others, whose papers should be consulted for a more complete 
presentation of the subject. 
The burrowing habit may be of advantage in several ways. 
Many seedlings possess contractile roots, by means of which they 
reach a suitable depth of soil. In certain plants which produce 
stolons or runners, root contraction is also an important factor. 
When the stem touches the ground it strikes root and is soon 
pulled beneath the surface. 
Rhizomes may develop horizontally, at right angles to the 
direction of gravity, without being influenced in a mechanical 
way. There are, however, many, like the long rhizomes of Iris 
versicolor , which are continually growing upward, but contractile 
roots developed on the under side continue to pull them down 
into a horizontal position. In such forms as Trillium grandiflo- 
rum the short rhizome is not only kept horizontal, but is buried 
deep in the earth by the strong contraction of the numerous long 
roots growing out of the under side. 
There are rhizomes and bulbs which develop vertically, and 
would thus grow out of the ground. But as the stem elongates 
or dies away below, the newer part is pulled backward by a whorl 
of contractile roots which grow out on the young nodes near the 
upper end. Very striking examples of this type are Botrycliium 
obliquum and Spat hy evict foetida. 
In some plants there is a main tap-root which continues to 
contract for a long time, and thus keeps the growing points 
at or near the surface. This may occur in acaulescent herbs 
or in crownformers like Aquilegia canadensis and Taenidia 
integcrrima . 
The following plants have prominent root contraction : 
Botrychium obliquum. Trillium undulatum. 
John H. Schaffner. 
Botrychium (lissectum. 
Arisaema triphyllum. 
Arisaema dracontium. 
Spathyema foetida. 
Zvgadenus elegans. 
Veratrum woodii. 
Hemerocallis fulva. 
Trillium sessile. 
Trillium recurvatutn. 
Trillium nivale. 
Trillium grandiflorum. 
Trillium erectum. 
Trillium cernuum. 
Hypoxis hirsuta. 
Iris versicolor. 
Iris hexagona. 
Allionia nyctaginea. 
Aqjuilegia canadensis. 
Aquilegia vulgaris. 
Gentiana atidrewsii. 
Plantago major. 
Taenidia integerrima. 
Lacinaria squarrosa. 
Mesadenia tuberosa. 
Taraxacum taraxacum. 
Taraxacum erythrospermum. 
