BOTANICAL STEUCTURES. 303 



Cfar^ener, or to the more recent work by the late Mr- 

 Sweet, entitled The Botanical Cultivator. The common 

 means of propagation is by cuttings, inserted in earth 

 or sand, and covered, if necessary, with bell-glasses. 

 A few sorts are increased by grafting or layering. 

 Nearly all may be raised from seed, large quantities 

 of which are annually imported from abroad. It may 

 be added many green-house plants ripen their seed in 

 this country, and the collectiDg of such seeds is too 

 often neglected. 



Many of these plants require shifting and fresh earth 

 twice a year ; all of them should be repotted once a year 

 at least. It is the common practice to examine their 

 roots in spring or the early part of summer, and re- 

 moving the matted fibres, to put them into larger pots 

 if necessary. As room is extremely valuable in limited 

 green-houses, it is desirable that the plants should be 

 kept of a moderate size; and they are, therefore, rather 

 to be under- potted than otherwise. Many of the free- 

 growing plants require to be shifted again in August, 

 at which period of the year it is considered preferable 

 to repot those which need to be disturbed only once 

 a year. During the summer months, a great proportion 

 of the inmates of the green-house are placed in the open 

 air, on a spot paved with flagstones, or laid with coal- 

 ashes, to prevent the entrance of earth-worms into the 

 pots, and the spot selected should be well sheltered 

 from high winds. Meanwhile, their place in the green- 

 house maybe occupied by balsams and other tender 

 annuals of a showy character. On the approach of 

 winter, the plants are again placed under cover. All 

 that is necessary in the management of the green-house 

 in winter is to keep up a steady but^ very moderate 



