215 



South America, Mexico, and the West 

 Indies ; and as they will thrive in a 

 much lower temperature than the 

 Dendrobiums, and some of the other 

 Orchidacese, they are very suitable 

 for a small hothouse. All the kinds 

 may be grown in pots, though some 

 of the smallest appear to thrive most 

 tied to pieces of wood and hung from 

 the rafters. The soil should be turfy 

 peat, broken in pieces about the size 

 of gooseberries, and mixed with an 

 equal quantity of potsherds broken 

 somewhat smaller. The pots should 

 be large, and filled a third of their 

 depth with broken potsherds, rather 

 larger than those mixed ^^•ith the soil. 

 Grreat care should be taken in repot- 

 ting any of the Oncidiums, as the 

 roots will be found to adhere strongly 

 to the sides of the old pot, and thus 

 are easily broken. To prevent this, 

 the plants should be shifted as seldom 

 as possible ; and when shifting is in- 

 evitable, they should be kept without 

 ■water for several days beforehand, so 

 that the plants may be in a flagging 

 and feeble state, and their roots have 

 less power of adhesion. All the On- 

 cidiums should be regularly watered, 

 but they should not often be syringed 

 overhead, as they are very apt to rot 

 if any water should lodge in the cen- 

 tre, or what gardeners call the heart, 

 of the plant. 



The commonest kinds of Oncidium 

 are 0. flexubsuni, a very beautiful 

 species, with a long, much-branched 

 panicle of bright-yellow flowers ; 0. 

 crispum, the flowers of which are of 

 a copper colour, and much undulated 

 or curled ; 0. altissimum, with a 

 very long flower stem, somewhat 

 branched, and with yellow flowers 

 spotted with brown ; 0. liiridiun, 

 with a panicle of greenish -brown 

 flowers ; and 0. 'po-pUio, the flowers 

 of which are borne singly, on long, 

 simple and naked stalks. Besides 

 these, there are many species nearly 



allied to 0. altissinium and 0. luri- 

 dura; and there are also some dwarf 

 species, such as 0. triquetrura and 

 0. raniferum, the latter having 

 drooping racemes of very small flow- 

 ers. The colours are generally yellow 

 and brown, but 0. puIcheIluin,a,\eTj 

 beautiful species, has white flowers 

 tinged with pink, and 0. ti-iquetruin 

 has white flowers blotched with piir- 

 ple. 0. raniferum should be grown 

 on a piece of wood hung from the 

 rafters ; and 0. papilio, and some of 

 the other species, may be treated in 

 the same manner. 



Onobry'chis. — Leguminbsce. — 

 Saintfoin. Hardy perennial plants, 

 some of the species of which are pretty 

 and suitable for rock-work. 



Ono'^'IS. — Zer/uminosce. — The 

 KestHr.^row. — Littleherbaceousand 

 shrubby plants, some of which are 

 natives of Britain, and which have 

 generally yellow or pink flowers. 

 Most of the kinds should be grown 

 in peat, or in very sandy loam ; and 

 they are all suitable for rock-work. 

 Some of the kinds from the south of 

 Europe are rather tender ; but they 

 will all live in the open air, if they 

 have a slight protection during hard 

 frosts. 



Opera Girls. — See Ma>-ti'sia. 



O'PHRTS. — Orchiducece. — Dwarf 

 plants belonging to the terrestrial 

 Orchidete, with very curious flowers, 

 which always look as if an insect 

 were nestling in them. One of these, 

 0. apifem, looks as though a bee 

 were buried in the flower ; another, . 

 0. aranifera, has the lip in the form 

 of a spider; and in the third, 0. mus- 

 cifera, the whole flower resembles a 

 fly. — For the culture of these plants, 

 see O'px'His. 



Opu'xtia. — Cactacece. — The 

 Prickly Pear. — This is the hardiest 

 of all the genera of Cacti, as there 

 are some species which will live 

 in the open ground in England, with 



