518 ORCHIDS. 
may be grown in pots: these should vary in size according 
to the nature of the plants, such strong-rooting kinds as 
the Cypripediums and Orchis foliosa requiring a liberal 
amount of root-room, whilst the Ophrys, Serapias, and 
others, which have not much root, require considerably less 
room. It is best to put about five plants of these smaller 
kinds in a 6in. or 8in. pot. The pots should be well 
drained. The soil used for plants in pots should be 
specially good. 
Collecting.—The right season for collecting terrestrial 
Orchids is after the flowers are over and the leaves have 
begun to fade. The tubers should be kept in damp moss 
until they can be planted. 
Arethusa. 
A. bulbosa.—A swamp-loving plant from North America, 
and a pretty little Orchid for a fissure in a rockery. Its 
one-leaved stem is about 8in. high, and it bears a large, 
solitary, rosy-purple, scented flower, which develops in 
July. 
Calopogon. 
C. pulchellus is from the same country, and _ thrives 
under the same conditions, as the Arethusa. It is pretty 
in flower, but difficult to establish here. Its leaves are 
grassy, its stems rft. high, and two- to four-flowered. Each 
flower is tin. across, bright purple in colour, the sepals 
and petals spreading, and is peculiar in having the 
labellum at the top. It blooms in July or August. 
Cypripedium. 
For generic description the reader is referred to Chapter 
XXVIIL, p. 152. 
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