VON MARTIUS ON STOVE CULTIVATION. 808 
much as possible continuous daylight, in conformity to what takes place 
in their natural place of growth ; whereas 
13. The lower forest-vegetation demands a strong degree of direct 
light, and if equinoctial, or from hot tropical countries, a long-continued 
and uniform increase of heat. 
14. The ground-vegetation of various tropical and subtropical re- 
gions are subject, sometimes, to a very considerable reduction of tem- 
perature, owing to the powerful nocturnal radiation of heat; so that 
plants from thence, should be carefully separated from those, which are 
impatient of any considerable diminution of temperature. It is in this 
respect that mountain-plants from the tropics, will bear being associated 
with those of subtropical regions. 
15. As far as it is practicable, such plants only, as agree in their 
periods of vegetation, should be associated together in any description 
of house; especially in those cases, where the transition from one vital 
period into another, is very energetic, and where the state of rest is in 
consequence strongly marked. In short, plants of very different pe- 
riodicity, should always be kept apart from each other. 
16. In the reconstruction or arrangement of houses, the productions 
of one and the same native country ought, wherever possible, to be as- 
sembled together. It is advantageous to go beyond even the common 
classification of Cape of Good Hope houses, New Holland houses, etc., 
and to establish single floral regions, in separate buildings, or divisions 
of them. 
17. Whenever it is required to subdivide and accommodate a house 
for different cultures, those plants, which are nearest allied in their 
life-periods, ought to be grouped together; while others, which differ 
greatly in that point, should be kept farthest remote from each other. 
18. In selecting the proper site in a given locality, the first consi- 
deration should be, whether the intended building admits of being 
erected at right angles to the meridian, or at what declination from 
it; and consequently, what light can be obtained at certain times of the 
year, or the day. So likewise must attention be paid, to the peculiari- 
ties of the climate in which the garden is situated, in apportioning the 
different localities in the building itself. Under this head comes espe- 
cially the direction of the prevailing winds at different seasons, by 
which the temperature of one or the other aspect of the house may be- — 
come particularly lowered. 
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