6 
URTICACEZ.. 
ULMUS, L.—U. fulva, Mchx. ; Palisades ; Glen Cove, Coles ; Central 
Park, &. & P.-—U, Americana, L. ; common ; N. Y.—U, campestris, 
L. ; in abandoned grounds. 2 
CELTIS, Tourn.—f. occidentalis, L.; not uncommon; N. Y.; Glen ° | 
Cove, Coles ; Weehawken, abundant ; Closter, scarce, Austin ; : 
North Salem, Mead. q 
MORUS, Tourn.—M, rubra, L. ; Bloomingdale, Torr. Cat.; Chatham, — 
N. J., W. H. L. ; Glen Cove, Coles; Closter, scarce, Austin; 
Hoboken Heights, Ruger; Central Park, R. & P.—M. alba, 
L. ; rather common about the city, 86th Street, Astoria, Ho- 
boken, etc., W. H. L. ; Central Park, R. d&: P. 
9. Herbarium Suggestions—No. 5. Poisoning Plants.—All phenoga- 
mous plants, at least, are not only liable to be attacked by in- 
sects when in a dry state, but are pretty sure to be thus destroyed 
in time if not properly protected. The ferns appear to be mostly 
free from this danger, and it is not considered necessary to poison 
& Specimen of a fern, unless it be extremely rare. @ 
For poisoning we use a solution of corrosive sublimate in alco- 
hol, about one ounce of the sublimate to a quart of aleohol ; or the 
strength may be tested by dipping a black feather in the solution, 
which should not be strong enough to whiten the feather when dried. _ 
- Now there is one precaution with regard to the use of this solu- q 
tion, which sad experience leads me to insist upon at the outset:— 
corrosive sublimate acts upon all metals in common use, and forms 
a dark compound which stains anything with which it comes 12 
contact. Hence this solution should never be kept in a metallic 
vessel, nor be applied with brush having a metallic ring ; and all 
metals should even be avoided in every process to which the speci- 
men is subjected after poisoning, as, for instance, in gluing. 
To illustrate this danger, I will say that I once employed a per- 
son to glue a large lot of valuable plants, which I had poisoned, to 
my herbarium sheets. Aware of the danger referred to, I had pro- 
vided a glue-pot Jined with porcelain, although made of iron. 
When the job was done, I found, to my disgust, that the sheets of 
paper were ruined by dark stains in almost every part, and the 
specimens had to be soaked off and reapplied to fresh sheets. Up- 
on examining into the cause, I found that the porcelain lining of 
the pot had chipped off in places, exposing the iron ; the glue- 
brush, alternately dipped in the glue and then applied to the por _ 
soned plants, had brought the sublimate and the iron together, — 
and the unsightly color had been distributed wherever the plants 
or the towel used in pressing them down had touched the white 
paper. : ae 
__ The solution of corrosive sublimate having been prepared, the — 
Specimens may be either immersed or sprinkled. With valuable 
plants, I have sometimes poured the solution into a large, shallow, 
dinner plate, such as is used for joints, and immersed the whole 
specimen for a second therein. 
It is usually sufficient, however, and it is far more convenient to 
