210 
POLYPODIUM CALCAHEUM. 
two parts, and very old mortar and lime or sand¬ 
stone for the other two parts, with a free addition of 
silver sand. A good drainage must also bo secured, 
and the plant fixed firmly in the situation it is to re¬ 
main in. It likes a free supply of water overhead 
through the summer months, but to be withheld as 
winter approaches; and it must be ripened off to stand 
through that season. The above-particularised compost 
and directions will be suitable either for pot-culture 
or for cultivation on rockwork, where it will bear 
moderate exposure to the sun ; but, as with the P. 
alpestre, a thoroughly good drainage and a free supply 
of water will be necessary; the water, of course, not 
to be used while the sun is shining upon it. It thrives 
remarkably well in a greenhouse, and may he easily 
propagated by division. 
