1 74 
The Ohio Naturalist. 
[Vol. II, No. 3, 
Several varieties of the cultivated grape, Vitis labrusca L., 
were observed to prune themselves to a limited extent by the 
formation of transverse joints, corresponding to the leaf nodes, 
in the same way as was described for Ampelopsis cordata Mx. 
This is also true for the common riverside grape, Vitis vulpina 
L., which prunes itself quite extensively. It is probable that all 
of our wild grapes possess the process of self-pruning, although 
no further observations have been made on this point by the 
writer. 
In this place it may be well to call attention again to the for- 
mation of joints and cleavage planes in certain geophilous, her- 
baceous plants. These are especially remarkable in Psoralea 
floribunda Nutt, and Psoralea argophylla Pursh., and similar joints 
are no doubt formed in many other such plants. 
As is well known, the American mistletoe, Phoradendron 
flavescens ( Pli. ) Nutt., produces numerous joints, which from 
herbarium specimens appear to develop cleavage planes and thus 
prune off branches. The same appears to be true also to a more 
striking extent in the European Viscum album L. The writer 
has had no opportunity to study these plants in the field, but it is 
probable that the whole family of Eoranthaeeae would afford an 
interesting study along this line. 
It is curious that, in so recent a work as Bailey’s Cyclopedia of 
American Horticulture, no mention is made of the remarkable 
process of self-pruning in the article on artificial pruning. The 
subject is practically dismissed by the statements that “ nature 
prunes,” and that ‘‘dying and dead branches in any neglected 
tree-top are illustrations of this fact.” But no reference is made 
to the formation of cleavage joints and the cutting off of green 
branches, nor the perfect manner in which the scars heal over in 
many trees. The writer believes that horticulturists should 
study these processes with great care, since these natural phe- 
nomena will probably indicate fundamental principles which will 
be well worth considering when an attempt is made to approach 
the subject of artificial pruning in an intelligent manner. 
Ohio Tumble Weeds — The following plants should be added 
to the list of Ohio tumble weeds, as given in the Ohio Nat- 
uralist 1:129: 
Baptisia australis (E.) R. Br., perennial, frequently acts as a 
tumble weed, although it does not seem to develop a special 
cleavage joint in the stem. 
Solatium rostratum Dunal., annual, makes a good tumble weed. 
Sisymbrium altissimum L., Tumbling Mustard, has been 
reported from eastern Ohio by L. D. Stair. — J. H. S. 
