ON THE CONSTITUENTS OF BULBS. 
83 
The above description of the constituents and evolutions of 
bulbs is applicable to any of that tribe of plants so called ; 
although there are several modifications. Some are remarkably 
rotund and succulent, as the Spanish onion and hyacinth ; others 
more lank in shape, and seem chiefly composed of the basis of the 
full grown or former leaves, as the leek and crinum. These 
different forms seem to be adaptations to their manner of growth, 
or durability of their annual or periodical products, and which is 
determined by the climate or soil of which they are natives. 
The bulbous form appears to be a provision of nature for se¬ 
curing them against the parching heat of summer, which is their 
season of rest. In southern latitudes, where the sun’s heat is 
intense, were their vital part not protected in a succulent bulb, 
they would be in danger of being withered up and killed during 
the dry season. The bulb also acts as a reservoir of aliment to 
serve and assist in the next growing season. It is this pause in 
the growth which enables the florist to raise them from the soil 
and keep them, as they would be in their native countries, 
perfectly dry until the autumn rains set in, when they are again 
planted. And though this removing them from the ground 
be not a natural proceeding, yet it operates favourably on the 
constitution of the bulb, by secluding it from atmospheric 
influence, and thereby reserving its energy, which, when again 
planted in fresh and suitable compost, induces free and vigorous 
growth. 
A bulb is distinguished from a tuber in having its vital part 
covered by thick fleshy scales like the hybernacula of buds, folded 
over, and involving each other like coats, each being distinct and 
separable from the others ; whereas a tuber is a solid mass of 
mealy or starchy matter, having eyes or buds seated in a crown, 
or dispersed over the surface, and without any appreciable cover¬ 
ing except the first leaves in which the flower is involved previous 
to expansion. A tuber may be divided into several portions, 
each of which, if it contains an eye, will become a distinct plant, 
exactly like the radical plate of a bulb, the smallest portion of 
which, if removed with a scale or leaf, will survive and become 
an independent bulb. Even if the flower stalk of a narcissus be 
pulled out from the centre of the leaves, with a small bit of the 
plate attached, and planted in loose soil, it will become the nucleus 
of a new bulb. Some of the lilies have wonderful powers of repro- 
