246 Encyclopaedia of Gardening 



Botanical Magazine, t. 521). Pannonicus, with purple and white 

 flowers in May, I ft. high, is also useful. They thrive in light 

 loamy soil, and are propagated by seeds or division in spring. 



Osmanthus (osman-thus, from osme, perfume, and anthos, flower. 

 Ord. Oleaceae). Evergreen shrubs, of which ilicifolius, a variety of 

 Aquifolium, is the best; there are several forms, differing in the 

 shape and colour of the leaves, including one with variegated 

 foliage. Fragrans (syn. Olea fragrans) has white perfumed flowers, 

 and not being quite hardy is sometimes grown in pots. They like 

 sandy loam, and may be propagated by cuttings inserted in sandy 

 peat. 



Osmunda, Royal Fern (osmun-da, a Celtic deity. Ord. Filices). 

 The Osmundas are among the most stately of ferns, and some are 

 hardy. The clusters of sporangia near the tips of the fronds have 

 earned for them the name Flowering Fern. Regalis is the finest of 

 all, and this makes a noble companion for the Ostrich Fern in a cool, 

 sheltered, humid spot at the waterside, where it may be found at a 

 height of 7 or 8 ft. It is the handsomest of all the British ferns, 

 and there are several forms of it, notably cristata, gracilis, and 

 palustris. Bipinnata and cinnamomea are handsome Osmundas, 

 but they are not hardy. 



Ostrich Fern. See Onoclea. 



Ostrowskia magnifica (ostrow-skia. Ord. Campanulaceae) . 

 A beautiful Campanula-like hardy herbaceous perennial, growing 

 3 to 5 ft. high, and bearing large pale blue flowers in summer. It 

 likes a sheltered but sunny spot, and a friable loamy soil, with 

 water in dry weather. Propagation is by seeds in spring. It seeds 

 freely where it makes itself at home. 



Otaheite Orange. See Greenhouse Orange. 



Ourisia (ouris-ia. Ord. Scrophularineae) . A small genus of 

 hardy herbaceous perennials, one species of which, coccinea, is a 

 beautiful little plant, bearing its scarlet flowers in abundance in 

 summer on stems about a foot high. It loves moist, peaty soil in a 

 shady place. Propagation is by seed and division in spring. See the 

 Botanical Magazine, t. 5335. 



Ouvirandra, Lattice-leaf Plant (ouviran-dra, from the native 

 name for water-yam, ouvirandrano. Ord. Naiadaceae). A singular 

 aquatic, whose lace-like, transparent green leaves are of great 

 interest and no little beauty. It should be planted in loam and 

 submerged in water that is kept lukewarm, and should be given a 

 shady position in a warm house. The species is fenestralis, and 

 modern botanists call it Aponogeton fenestralis. 



Ovary. The part of a flower, lying below the pistil, which con- 

 tains the unfertilised seeds, called ovules. In plants where it is 

 formed within or above the petals it is called a superior ovary; 

 where behind or below, inferior. The ovary is considered to have 

 developed, like the petals, from a leaf. 



Oxalis, Wood Sorrel (6x-alis, from oxys, acid, in allusion to the 

 acidity of the leaves. Ord. Geraniaceae). A large genus, variable 



