ALPHABETICAL LIST OF PLANTS 315 



Other varieties worth growing and requiring similar treatment 

 are: O. muscifera (Fly Orchis), O. aranifera (Spider Orchis), 

 O. Arachnites^ O. bombilifera (Humble Bee Orchis), and O. Trolli. 



Opuntia (Cactaceae) 



Plants of the Cacti order, some of which are hardy in the warmer 

 districts, and many are very beautiful when in flower. They all 

 require a very hot, dry situation in light soil, with plenty of lime 

 rubbish mixed with it. They should be kept dry during the winter. 

 As these can scarcely be considered typically rock plants, but are 

 more generally associated with tropical vegetation, it would be 

 better to group, in a spot reserved for them, when the needed pro- 

 tection during the winter could be more easily given. Most 

 nurserymen keep them, and a selection can be obtained. 



Orchis (Orchideae) 



Many of the terrestrial Orchids are very beautiful for the bog and 

 rock garden. Orchids, even our own native species, are generally 

 considered difficult to cultivate. This, however, is due not so much 

 to the nature of the plant, as to the time of planting. They should 

 never be moved when in flower or making growth, which so fre- 

 quently is just the time when they are transplanted, with the result 

 that they die, and thereby get a bad reputation. August and 

 September are the best months for planting them. The following 

 selection will give some of the hardiest and best species : — 



(9./^//^j«.— Rich, rather damp, heavy loam in a sheltered nook. 

 Dense spikes of rosy-purple spotted flowers, rising about i8 inches 

 from the ground. A very handsome species, flowering in May. 



O. latifolia (Marsh Orchis).— Damp, rather rich, boggy soil, in 

 partial shade. Purple or red flowers in long, dense spikes, coming 

 into bloom about June. There are several good varieties of this — 



O. I. z«^<3:r;2<2/^.— Flesh-coloured. 



O. L sesguzpedalzs.-— Violet-purple colour, in very long spikes. 



O. laxz/lora.— Moist loam and peat in partial shade. Loose 

 spikes of rich purplish-red flowers in May. Handsome. 



O. 7naculata. — The well-known " Spotted Orchis " will be found 

 an excellent plant for the bog garden. The variety superba is very 

 fine. 



O. papilionacea (Butterfly Orchis). — Heavy loam and limestone. 

 Flowers reddish-purple. 



Other varieties that can be grown are — 



O. militaris and O. purpurea^ in limestone and heavy loam. 



O. mascula, O. Pyramidalis^ O. sambucina^ and O. spectabilis^ 



