1918] BRIEFER ARTICLES 69 
HEALTHY AND SICK SPECIMENS OF BRYOPHYLLUM 
CALYCINUM 
Those who have worked with Bryophyllum calycinum, WALKER, 
Der Vries, GOEBEL, the writer, and probably many others, have all 
noticed that the leaves of Bryophyllum which form shoots when iso- 
lated will rarely or never do so when in connection with a normal 
and healthy plant. Miss E. L. Braun' makes the following statement: 
Pot-grown plants of B. calycinum in the writer’s possession have frequently 
grown both shoots and roots from leaf notches while the leaves were in con- 
nection with the plant. Early in the spring of 1917 a large plant of Bryo- 
phyllum began to produce shoots from the leaves more abundantly than the 
plants often do. The accompanying photographs were taken May 12, when 
shoot production had reached its maximum. It was not necessary to induce 
the notches to grow; they grew freely under ordinary room conditions, and with 
only the usual attention which a pot plant in a residence receives. 
A number of the leaves of the plant produced shoots from all the notches 
or from all except the basal notches, a phenomenon which, to accord with 
Loep’s theories, should take place only under very special conditions. The 
plant appears to be a “healthy plant,” as healthy and vigorous a plant as the 
writer has ever seen. Whether or not it is a ‘‘normal plant,” as a norma 
plant is conceived of by Logs, is difficult to say, for nowhere does he define a 
“normal plant.” He does state: ‘If, however, the flow of substances in a 
plant is abnormal, either because the roots or the apical parts or both have 
suffered, a growth of shoots may occur in moist air from the notches of leaves 
which are in contact with the plant.” There is no indication that either the 
roots or the apical parts have suffered; the plant appears healthy, and has had 
no accident. 
A glance at the photograph accompanying Miss BRAuN’s statement 
will show to those familiar with ‘normal’? Bryophyllum that the plant 
observed and photographed by Miss BRAUN was a sick specimen. The 
normal stem of Bryophyllum calycinum is perfectly straight and vertical 
(and unbranched). The specimen observed by Miss BRAUN has not a 
single straight stem. Stems so weak as not to be able to grow vertically 
upward are certainly abnormal in regard to nutrition. The bend in the 
stems acts like a partial block to normal circulation. Such sickly bent 
stems behave to all purposes like isolated pieces of stems whose leaves 
will in time give rise to shoots.—Jacques Logs, Rockefeller Institute for 
Medical Research, New York City. 
* Bor. Gaz. 65: Igt. 1918. 
