29 
veloped by its erosion foster a brilliant and peculiar spring 
vegetation found only in the region of limestone outcrops. Such 
a development has been lacking in the Local Flora Section, but 
through the kindness of Mr. Augustus Wittingham, of Andover, 
New Jersey, we have obtained sufficient rock to construct a 
ledge or embankment, which will simulate a natural outcrop and 
provide favorable places of growth for such plants as the sharp- 
leaved hepatica. There are a great many flowering plants and 
ferns which can grow under no other conditions. This wall is 
now being constructed at the eastern end of the Section and 
should be ready by mid-summer of this year. With the acces- 
sion of this limestone area the plant habitat groups of the New 
York region will have been essentially completed, although much 
remains to be done in the mass production of plants and in the 
constant amelioration of soil conditions. 
During the past year there has been a good deal of thinning 
out of underbrush and of some trees, but more thinning is re- 
quired from year to year. This is especially true of the wood- 
land, which was planted about 1918 and which has now reached 
some degree of maturity. The tulip tree (Liriodendron) and the 
sweet gum (Liguidambar) tend to grow at a much more rapid 
rate than any of the other trees; the tulip tree especially tends 
to quickly dominate the slower-growing oaks and maples. _ In the 
course of the year the sandy border of the pond has been renewed 
and replanted. Portionsof the bog have been dug out and replaced 
with fresh peat, a procedure involving a considerable amount of 
replanting. In a section along the brook, ground has been pre- 
pared to a considerable depth and planted with Virginian cow- 
slip. Another portion of ground adjacent to the DeVries me- 
morial tree will require some change incidental to the construc- 
tion of an area for the growth of marsh marigold and wild 
hellebore (Veratrum viride 
A portion of the Local Flora area is exposed to the sweep of 
cold winds from the northwest. This factor, together with the 
unusually dry spring, contributed to the damage of a number of 
plants, chiefly our specimens of Juniperus communis, our largest 
bog spruce (Picea mariana), and some of the swamp cedars 
(Chamaecyparis). The growth of our northern plants, such as 
Sener 
