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undigested experiments made on the Arachis hyp&gcea , or “ ground nut;” and 
his conclusions are, as might be expected, meagre and unsatisfactory: namely, that 
darkness may be necessary to perfect the maturity of the pod, and that it may 
further absorb “ something” from the earth, and this “ something” may be water. 
To those who have attended to the phenomena of this extraordinary plant, the 
true cause is evidently to secure the uniformity of temperature maintained by 
terrestrial warmth. The temperature of the earth and the air are very diffe¬ 
rent : that of the former will remain comparatively uniform during the night, 
wdiereas the latter will be subject to incessant vicissitudes. It is thus that, in a 
medium of uniform temperature, immature seeds may be ripened; and in this 
manner have I matured the green fruit of the Bannana * a thousand proofs might 
be adduced in verification. The Colchicum autumnale ripens its seed-vessel and 
contents below the surface of the ground, and if circumstances do not permit the 
cyclamen to bury its seeds for the same purpose, it is interesting to observe how 
carefully it coils the stalk round the vessel, so as effectually to conceal it; not 
merely to shroud it in darkness, but to preserve externally the uniformity of tem¬ 
perature maintained by the plant. 
On the same principle are similar phenomena developed in aquatic vegetation. 
The Ranunculus aquatica matures its seeds below the surface, the Valisneria 
spiralis retracts its seed-vessels to the bottom of the river, and the Nelumbium , 
Nymphea , and Nuphar withdraw their seed-vessels from the surface, to escape 
from the effects of radiation, and take advantage of a medium comparatively 
unchangeable and free from those alterations to which the aerial medium is con¬ 
stantly subject. Sometimes bags or bladders of air fulfil the purpose of insulation, 
as in the seed-vessels of the Passiflora cerulea and Colutea frutescens ; at other 
times, silk and cotton are the means employed; examples are supplied in the 
Asclepias Syriaca , Gossypium herhaceum , and “ Silk-cotton Tree.” We have 
an evident proof that this is the intention, or at least the inference amounts to 
probability, in the fact that we meet with the same provision in denizens of the 
desert, between the tropics, as in arctic and antarctic lands ; thus, the seeds of the 
Stapelia are enveloped in a silky down, as well as those of the Lilliputian Wil¬ 
lows, on the shores of West Greenland. 
The Economy of Bulbs. 
Under this section it is not my intention to enter upon a description of the 
various structures presented by bulbs, or the different offices or functions they are 
destined to fulfil. My task, at present, will be confined to the provisions in their 
economy to meet extraordinary contingencies. The distillatory function of the 
Calla AEthiopica and Agapanthus umbellatus will be remembered; but the 
change of place or position is not less remarkable. While plants generally 
