TREATMENT OF EPIPHYTAL ORCHIDS. 17 



The blocks on which the plants are grown should be of those 

 kinds like the apple or pear, with a smooth surface, and in a 

 fresh state when the plants are fastened upon them. The fast- 

 enings should be eftected by copper wire and nails ; old dry 

 blocks^ with rough bark, or charred ones, are bad, on account of 

 their easily becoming too dry, particularly the charred ones, 

 whose black surface absorbs heat, which is injurious to the 

 young roots, especially in summer. 



Native plants, which frequently spring up about the roots of 

 Orchids, on blocks or in baskets, are useful indexes to the state 

 of the soil as regards moisture in summer, for they soon flag 

 with lack of moisture. 



Blocks or baskets are perhaps, in the majority of cases, best 

 for true Epiphytal Orchids, but on these they require more at- 

 tention, in regard to moisture, than when grown in pots. In 

 tlie case of Stanhopeas, however, it is absolutely requisite to 

 grow them upon blocks, as their flowers grow downwards. 

 Again with Aerides, and all true air plants having thick fleshy 

 aerial roots, it is necessary to place them upon blocks or in 

 baskets, and to suspend them from the roof, so that their roots 

 may grow freely in the damp atmosphere, for if confined under 

 the soil they soon perish. Fibry peat, moss, or sphagnum, when 

 used for the purpose of covering the roots, is of no other use 

 than that of retaining moisture. Sphagnum and moss of all kinds 

 is bad, if not fully exposed to the atmosphere, and soon becomes 

 mouldy : it should only be used on blocks or on the outsides of 

 the baskets. 



In suspending the blocks, always place them perpendicularly, 

 and the baskets quite horizontally; and invariably have them* 

 taken down and examined every third day in summer, and once 

 a week in winter, to see if they want watering. This must be 

 done independently of syringing, for some parts of the blocks 

 may be found to be quite moist enough, while other parts are 

 dry. Some Orchids are the better for being placed near the 

 glass when in a state of rest, and for being fully exposed to the 

 light for a short time, particularly such plants as Barkerias, 

 Stanhopeas, and other deciduous or subdeciduous kinds ; it is a 

 mistake to suppose that all Orchids should be rested during 

 winter — each should be rested when it naturally requires it, 

 whether it be winter or summer ; some kinds bloom during the 

 winter months, and consequently require rest at another season. 

 Lselias are of this kind. 



The soil of plants in pots, when placed upon the smooth 

 surface of slate shelves, is apt to become too moist during 

 winter, owing to the water not being able to pass off" freely 

 through the hole in the bottom of the pots, or from their absorbing 



VOL. IV. c 



