Commons near Croydon, and their Flora, _ 5 
The chalk downs support a fine close velvety herbage composed 
of a much larger number of species of plants than are to be met 
with on sandy, clayey, or peaty soils. ‘he juniper is the charac- 
teristic shrub, and among other plants peculiar to a chalky soil . 
may be mentioned the rock rose, the small burnet (Poteriwm 
Sanguisorba), the horse-shoe vetch (Hippocrepis comosa), the 
dropwort (Spirea Filipendula), and the small scabious (Scabiosa 
Columbaria). The plants of wet situations are, as might be 
expected, absent on our dry chalk commons. 
The following are further particulars about the principal 
commons in our neighbourhood :— 
Suirtey Hinus.—Area of space dedicated to the public, 87 
acres; altitude 840-480 ft. (0. p.);—-consist geologically of a 
bank of rounded flint-pebbles, formed on or near the old tertiary 
sea-shore, and more than 50 ft. thick. The most prominent 
features of these hills are the steep rounded slopes and deep 
intersecting hollows on their north side—i. e. in the direction of 
the dip of the strata. In this respect they differ from the other 
commons and tracts of Oldhaven pebble beds in this neighbour- 
hood, which, though they may have an abrupt escarpment on 
the south side, at the outcrop of the pebble bed, as at Hayes and 
Keston Common, have only a gradual slope northwards in the 
direction of the dip. The peculiar formation of the Shirley 
Hills is probably due to the way in which the pebbles have been 
originally heaped up at this spot. The pebble bed varies greatly 
in thickness; thus in the Park Hill Rise section, described by 
me in a paper read to the Club in 1896, it was found to vary 
from 4 in. to 11 ft. in thickness in less than a quarter of a mile. 
Botanically, the chief rarities at Shirley Hills are found in the 
enclosed portion near Oaks Road, and therefore hardly come 
within the limits of my paper; but many interesting plants may 
be found, especially in the damp hollows. Some, however, have 
disappeared: thus, some years ago I saw young plants of the 
northern hard fern (Lomaria spicant), but have not found it in 
recent years. Some of the larger terrestrial mosses and lichens 
are plentiful, and in the sides of ditches in the damp hollows 
are to be found several species of scale mosses (Jungermanniacea). 
These may be found in fruit in spring; and their black shining 
capsules, borne on silvery thread-like stalks, and ultimately 
splitting into four valves, and discharging spores mingled 
in spiral threads, form interesting and beautiful microscopic 
objects. 
Fungi are plentiful in autumn; among them may be mentioned 
the beautiful but poisonous fly agaric, with its tall ringed stem 
and scarlet cap dotted with white warts; Sparassis crispa, a rare 
and curious sponge-like species; and Torrubia militaris, a species 
parasitic upon caterpillars. The mycelium ofthis fungus penetrates 
