263 
imens. Such a great weight is certainly prejudicial to the scientific 
excellence of their specimens, crushing and jamming together in an 
undistinguishable mass all the tenderer portions, while all the ex- 
ternal excellencies for which they sought could have been fully 
secured by the moderate pressure recommended. 
To supply the weights, various heavy articles may be used, as 
bars of iron ; a number of stones weighing from 10 to 50 lbs. each, 
and roped for convenience of handling, if desired; boxes filled with 
sand, stones, old iron; etc. The writer has half a dozen or more old 
fashioned scale weights, with their rings remaining, weighing 14, 28, 
and 56 lbs. respectively. These, with stones, he finds answer every 
purpose. 
In preparing a package for the press, first lay down two driers, then 
put on a sheet with specimens, next two more driers, then another 
specimen sheet, andsoon. Thenumber of driers interposed between 
the sheets of specimens will depend on the thickness and succulence 
of the plants. On an average two driers are sufficient, but if the 
specimens are coarse and fleshy, more will be needed,—a packet with 
the driers, or even more packets in drying certain plants with thick 
stems, large heads, etc. If these packets should not be at hand, 
uniform pressure may be secured by placing thick strips or cotton 
batting about the edges of the package. Ringlets of cotton may be 
used for some of the larger headed Composite, if perfect flower spec- 
imens are derived. With a little care in adjusting the larger speci- 
mens in the package, so that the thick parts are not too much above 
each other, and with the use of newspaper packets, I have very rarely 
found it necessary to employ thick strips or cotton to secure an 
equable pressure. In plants containing little moisture, and in those 
which part with it readily—as the sedges, grasses and many of the 
ferns and aquatics—one drier between the specimens, after the first 
24 hours, will be all then required, as it will in most of the other plants 
after the ‘third day, especially if the driers are changed as directed. 
For the press recommended, with weights at top, the pile should 
rarely be carried higher than 18 or 20 inches; if carried much 
beyond this point, the pile is apt to become shaky and the pressure — 
unsteady : better start another press to hold the surplusage. It is 
also well not to make the various packages or sections which com- 
pose the pile too large,—not over 6 inches in thickness, the writer’s 
are seldom over 4 inches,—as the plants dry better in small pack- 
ages on account of the pressure being more evenly distributed. 
§ 263. New or Little-known Ahly of the United States. 
No. 
In the first part of the “ Ferns - North America,” when _Speak- 
ing of Asplenium serratum,1 made the observation that ‘ ‘it can 
scarcely be rash to hazard the conjecture, that there are yet in the 
swamps and hummocks of Florida more undiscovered tropical ferns 
to reward the diligent explorer.’” I now have the pleasure of 
announcing a four-fold fulfilment of this prediction. 
- 12. Ceratopteris thalictroides, Brongniart. —This plant, which is 
one of the most peculiar of Ferns, was discovered last July by Dr. 
