May t, X99X 
Rooting Stems in Timothy 
177 
NAMES NEEDED FOR DIFFERENT TYPES OF ROOTING STEMS 
The question arises as to what name should be applied to rooting stems 
in timothy. Stems produced above ground are runners or stolons, 
according to a commonly accepted definition of these terms. However, 
the examples given in connection with the published definitions are by 
no means typical of the phenomenon that occurs in timothy. As for 
the underground rooting stems, those of the first type discussed in this 
paper are not essentially different from those found for example in 
Kentucky bluegrass and red fescue, except that they do not develop 
normally but are induced by unusual conditions. These stems are 
formed by the elongation of one or more of the lower intemodes of the 
shoots which normally remain unelongated. The elongation of the inter¬ 
nodes is for the purpose of placing the new shoots in a more favorable 
place for growth and development. This might be said to be the func¬ 
tion of all underground stems, except possibly tubers, corms, and the 
like. But true rhizomes, by which are meant underground stems that 
root at the nodes and produce stems or leaves progressively, have in 
addition to this another definite function, that of reproduction. It would 
appear desirable, therefore, to designate by some specific name the under¬ 
ground rooting stems of timothy and other grasses that develop by the 
elongation of the basal intemodes only under unusual conditions and 
for the purpose of placing the new shoot in a more advantageous location. 
Mr. C. V. Piper has suggested for such an organ the name “topothete,” 
a Greek word from topos, a place or location, and thetu, meaning to 
place. It is evident from a study of the various terms applied to rooting 
stems and the definitions of these terms that those who formulated them 
did not appreciate sufficiently the fact that there are at least four distinct 
types of rooting stems produced by grasses and other plants, two kinds 
above ground and two kinds underground. Since the existing terms do 
not meet the needs of the case, the following names are proposed with 
the hope that they will be given favorable consideration. 
Determinate rhizome. —An underground stem which is disposed to 
root at the nodes and from which a single aerial shoot or tuft of shoots 
is produced; example, Kentucky bluegrass (Poa pratensis L.). 
Indeterminate rhizome. —An underground stem, thickened or other¬ 
wise, which roots at the nodes and produces aerial shoots progressively; 
example, quack grass ( Agropyron repens IN¬ 
DETERMINATE SToeon. —An above-ground stem which roots at the 
nodes but does not produce aerial shoots progressively. Under this is 
included lax culms that have come in contact with the soil and have 
rooted at the nodes; examples, Paspalum dilatatum D and crab grass 
(Syntherisma sanguinalis L.). This type of rooting stem is common in 
red top {Agrostis alba D) and other species of Agrostis. These grasses, 
however, also have indeterminate stolons. 
