33 
An Abnormal Form of Carya porcina, Nutt.— The accompany- 
ing Fig. I represents a longitudnal section between 
the two valves, and shows the hull, shell and kernel- 
zones of a nut from an abnormal form of Carya por- 
cina. The hull breaks off abruptly into a neck 
which is often half an inch long. There is a long 
point of the shell projecting into the neck of the 
husk. The husk of this form splits at maturity into 
only two valves, one of which is entire and covers 
from two-fifths to one-half of the nut. The 
other valve varies from three-lobed, to three- 
parted, but the lobes are always grown together 
at the base. There is a prominent ridge, which 
runs around the nut betw^een the valves, and 
which in some specimens amounts almost to a 
wing. There are also lesser prominences. A 
cross-section of the nut would have the appear- 
ance of a semi-circle attached to a semi-hexagon. 
The nut has a wrinkled appearance. The hull is 
cinereous in color or pale green. The leaves are 
glabrous, and large for this species, and of a 
darker green than those of the common form. 
The specimens were found on a tree in the 
campus of the Arkansas Industrial University, 
and near a tree with nuts of the forms represented 
in section in Fig. 2. 
Fig.l, 
Ft<), 2 
Fayetteville, Ark 
F. L. Harvev 
Botanical Notes. 
The Formation of Gu/n in Trees.— ^\r James Paget lias drawn 
attention in the McdicaTTimcs to some remarkable investigations 
made by Dr. Beijerinck in connection with the formation of gum in 
trees, and lately published by the Royal Academy of Sciences at Am- 
sterdam. Dr. Beijerinck found that in the peach, apricot, plum, 
cherry, or other trees bearing stone-fruits, the formation of gum may be 
caused by inserting a portion of the gum under the edge of a wound 
through the bark. The observation that heated or long-boiled pieces 
of gum would not produce this effect, and that wounds made in the 
bark of the tree did not produce gum unless a portion was first intro- 
duced into it, led him to suspect that the formation of gum was due 
to the presence of Bacteria or other living organisms. On micro- 
scopical investigation he found that only those pieces of gum contain- 
ing spores of a highly organized fungus, belonging to the Ascomycetes, 
had the power of conveying the gum disease or gummosis, and that 
these spores, inserted by themselves under the bark, produced the 
same pathological changes as did the pieces of gum. The fungus 
has been examined by Professor Oudemans, who has ascertained it to 
be a new species, and has named it Coryneum Beijerinckii. Its chief 
characters consist in the fact that it has a cushion-like stroma, com- 
