ON AXIAL ABSCISSION IN IMPATIENS SULTANI AS THE 
RESULT OF TRAUMATIC STIMULI 
Ross Aiken Gortner and J. Arthur Harris 
A considerable part of the very extensive literature of abscission 
pertains to the normal separation of the leaf from its axis, or of the 
leaflets of a compound leaf from their common petiole upon the 
approach of winter. Fifty years ago, however, von Mohl^ beginning 
with the observation that the leaves of plants which are put into the 
press for the herbarium sometimes separate from the stems, gave a 
most interesting account of some of the factors involved. Since then 
there has been a great series of scattered observations pertaining to 
normal and abnormal leaf fall. Recently, we have had the detailed 
experimental study of the fall of the corolla by Fitting.^ Quite dis- 
similar to the above studies but of some interest in the present connec- 
tion are the observations which have been published here and there 
on the self pruning of trees. 
Our purpose in this note is to call attention to abscission of the 
axis in Impatiens Sultani. This particular type of phenomenon we 
have never found described in the literature, but it may have been 
several times mentioned incidentally under titles which gave no clue 
to this part of their content, and which have escaped our notice because 
they are aside from our usual lines of work. We are fairly confident, 
however, that it has not been described in the Sultani. 
Impatiens Sultani^ like so many other species of this genus, has 
very watery, translucent stems, which take root readily, either when 
accidentally coming in contact with the soil or when cuttings are made.^ 
1 Mohl, H. von. Bot. Zeit. 18: 1-7, 9-17, 132-133, 273-277. i860. 
2 Fitting, H, Jahrb. Wiss. Bot. 49: 187-263. 1911. 
3 For Hooker's original description see Curtis's Bot. Mag. pi. 6643. For other 
figures see: Garden, 22: 208-209. pi. 352. 1882; Illustration Horticole, 30: 93-94. 
pi, 488. 1883. 
* The original plants were grown from seeds accidently secured in the soil in 
which other plants were packed for shipment. As far as we are aware it has not 
produced seeds under cultivation, but has been propagated since that time by 
cuttings. 
