490 Liliacee—Tulipa. 
paratory to opening, and which also produces leaves ; this bulb 
exhausts its juices according as the flower advances towards its 
end, and when that is reached, there is nothing left of it but 
the withered envelopes, which themselves soon decay and dis- 
appear: (2) the succeeding or replacing bulb, formed of very 
fleshy closely-packed scales, in the centre of which the leaves 
and flower-bud are in course of formation, and these are not 
fully developed till the following year; this bulb originates in 
the axil of one of the outer scales of the mature bulb; this, 
then, represents the second generation: (3) on one side of the 
last, and also in the axil of one of its outer scales, the bulb of 
the third generation already begins to show itself; it is fleshy 
and comparatively small, but enlarges in the course of the 
Summer. This would be the succession bulb of the following 
year, and would flower the third year, after having itself given 
birth to two generations of bulbs. The duration of each bulb 
is therefore three years, but it only flowers once. The Tulip 
is essentially monocarpic, and in the annual replanting, the 
bulbs which are confided to the ground are never those which 
have flowered in the Spring, but simply the succession bulbs 
which were produced the preceding season. Besides the suc- 
cession bulbs, which are in a measure the continuation of the 
same individual, other bulbs are produced around the full- 
grown bulb, but smaller and of a different shape, which we 
might term propagating bulbs. These are the offsets, properly 
so called, destined to live a separate and independent exist- 
ence, and become so many distinct individuals. 
The botanist Kunth, in the first half of the present century, 
enumerated thirty species of Tulip; but subsequent authors are 
far from accepting that number, some increasing it and others 
restricting it. The consequence is a very much entangled 
synonymy, and it is now almost impossible to clear up the 
fundamental species. These great divergences of opinion are 
due in the first place to similarity of the species, and then their 
variability under cultivation, and lastly the facility with which 
they intereross to form hybrids or fertile mules. All these 
causes taken together explain the almost unlimited number 
of varieties that exist in a wild or cultivated state, and the 
almost imperceptible shades by which they pass from one into 
the other. 
Mr. Baker estimates the cultivated species at seven, distin- 
guished as follows : — 
