ON THE CULTURE OF NEW AND RARE PLANTS. 
47 
only tends to fill up the pot, but also assists the drainage very much, which is a 
very important object, as these plants will not thrive at all, if the soil is allowed to 
become saturated with water, but on the contrary require a particularly free drain- 
age ; this done, a quantity of peat is procured, and also a quantity of broken 
potsherds ; some large pieces of this last are then put into the bottom of the pot, 
round the one which has been placed in the inside, then a good portion of smaller 
potsherds are put in on the top of these, and a layer of peat is then introduced, 
above which is placed another layer of potsherds, then another layer of peat, and 
so on till the pot is filled ; these materials are in some instances raised somewhat 
above the level of the top of the pot, and on them the plant is placed, the roots 
of which are then covered with equal parts of the same materials, and when the 
roots of the plant reach the edges of the pot, it is removed into one a size or 
two larger, according- as may be required. This system of potting answers re- 
markably well with most of the species of Oncidium, Zygopetalum, Dendrohium, 
&c., but many other species, viz. some of the last-named genus Dendrohium, 
some species of Sarcanthus, but more especially JBroughtonia sangumea^ and 
Renanthera coccinea, are placed on pieces of wood, which are suspended from the 
roof of the house ; the roots of these in process of time adhere to the wood and 
grow very luxuriantly ; this last system bears a striking assimilation to the natural 
habits of these plants, as they are for the most part found growing on the stems 
and branches of trees, from which they derive no nourishment, but subsist wholly 
on the surrounding atmosphere. Another system practised by Messrs. Rollison, 
is that of suspending plants (in wire baskets made for the purpose, or small 
rustic wooden ones of various shapes) from the roof of the house ; these baskets are 
filled with sphagnum, in which are planted several species of StanJiopea, Vanda, 
&c , to which this mode of treatment seems peculiarly adapted. In conclusion, we 
would just add that Messrs. Rollison allow no water to newiy-imported species, till 
after they have started growing, as watering in this state frequently tends to make 
them damp off. 
Our readers will by this time have perceived that the main features in Messrs. 
Rolhson's system of cultivation are, moderate heat, with a slight degree of mois- 
ture ; heating with hot-water, and potting for the most part in a mixture of pot- 
sherds and peat. We are aware that much more might be said on this interesting 
subject relative to the propriety of giving these plants a season of rest, bottom 
heat, and various other particulars relative to the manner in which they are 
generally cultivated, but as we wish to confine ourselves to our original object 
here (viz. that of giving an outline of Messrs. RoUison's system of cultivation), 
we would only just add, that for a proof of the success with v/hich it is attended 
we refer our readers to the plants themselves, where they will find a more demon- 
strative proof than any language of ours can express. 
Grevillea rosmarinifolia. This interesting plant, which has been known in this 
country for more than twelve years, and to which has always been assigned a situ- 
ation in the green-house, has at length been proved by Mr. Young, of Epsom, to 
be completely hardy ; he has for the last four years grown it in an open border, 
