LIST OF PLANTS 157 
to become dry, so a spray as fine as dew is used to 
avoid washing the seed away. Disas and Cypripediums 
are, perhaps, the easiest to handle in this way and the 
quickest to flower, but in all cases great care and un- 
limited patience are needed. 
ORNITHOGALUM.—Of these bulbous plants the Star of 
Bethlehem (O. umbellatum) and the cottage window 
Onion Plant (O. longibracteatum) are well-known but 
not by any means the most beautiful examples. Offsets 
from the old bulbs are generally relied on for propaga- 
tion, and in some kinds they are very freely produced. 
Orosus.—Plants of the Vetch family, useful in 
borders and on the rockery. All are increased by 
division in spring and by seed sown in April. 
OsMmAnTHUS.—These beautiful shrubs of the Olive 
family can be propagated by cuttings of half-ripened 
shoots inserted in a cold frame in autumn, or by graft- 
ing on stocks of Oval-leaved Privet. 
OsTROWSKIA.—O. magnifica, considered to be one of 
the finest of large-growing hardy perennials, is propa- 
gated by seed sown as soon as ripe in pots of light 
sandy soil ina cold frame ; also by root-cuttings, 3 inches 
long’, planted in a sheltered, sunny position in September. 
OUVIRANDRA (LATTICE-LEAF PLANT).—This most 
singular and always interesting submerged aquatic 
plant is successfully grown in a stove temperature with 
somewhat subdued light. Rain-water is used for 
preference, though tap-water that has been exposed and 
warmed answers very well. Propagation is easily 
effected by simply dividing the crowns, potting them 
in loam, and returning them to the water before they 
become dry. 
Oxa.is.—The cultivated annual kinds are increased 
