PLANTS WHICH IN DRYING STAIN PAPER. 39 
NOTHS on somME PLANTS WHIcH IN DRYING STAIN 
PAPER. 
By J. H. MAIDEN, Government Botanist and Director of 
the Botanic Gardens, Sydney. 
[Read before the Royal Society of N. 8S. Wales, June 6, 1906. } 
EVERYONE with herbarium experience must have made the 
observation that some plants stain the papers to which 
they are attached. Some, indeed, stain so persistently 
(e.g. Drosera Whittakeri) that the colouring matter will 
penetrate a dozen sheets or more. I have not observed 
that any botanist has drawn special attention to the 
matter and do not know that any one has given an explan- 
ation of these phenomena. I say phenomena, because the 
colouring or rather staining may arise from various causes, 
e.g. the presence of a specific colouring matter in the root 
or other portion of the plant, or the formation of a coiour- 
ing matter by oxidisation or other chemical change. The 
subject is of course one for a chemist, who will subject 
the paper itself to examination. 
It will be observed that the plants, in many cases, leave 
sharp photographic impressions on the paper. The 
phenomena arise from an emanation,—a dry distillation 
possibly. It is proper to point out that herbarium speci- 
mens in the National Herbarium, Sydney, are protected 
from insect ravages by means of naphthaline. No bichloride 
of mercury is used, but most plants are placed in a bisul- 
phide of carbon chamber before they are placed in the 
herbarium boxes. 
Most of the stains appear to be purplish, of varying 
intensity; the remainder are mostly greys and browns. 
The drying black of plants which do not stain is a cognate 
