Free Tulipomania by Mike Dash

was also the first to distinguish between early-, mid-, and late-flowering tulips, of which the first appear in March and the last not until May.
    Working from the solid foundation that Clusius provided, later botanists have added considerably to our understanding of the tulip. The flower has now been grouped with other bulbous plants such as the iris, the crocus, and the hyacinth and is classified among the Liliaceae. In all about 120 different species of tulip—and countless individual varieties—have been cataloged to date.
    In scientific works an important dividing line is drawn between what are known as
botanical tulips
, which originate in the wild, and
cultivars
, which are hybrids reared in the garden. In Clusius’s time the tulips that were produced in the United Provinces were a mixtureof wildflowers and an ever-increasing proportion of cultivars, the earliest of which were produced by chance crossings of two botanical tulips. Botanists have been able to identify fourteen different species of wildflowers as the building blocks that produced the flood of Dutch cultivars that adorned the seventeenth century. Not all played an equal part in creating this diversity. Some botanical tulips produce hybrids more readily than others, and the most malleable species that had found their way to the Dutch Republic included the Persian tulip—today known in Clusius’s honor as
T. clusiana
—the tapered tulip,
T. schrenkii
, and the fire tulip,
T. praecox
. Genes from these species were present in a large proportion of the cultivars that excited admiration in the Netherlands, but in truth Dutch tulips had been produced by crossing flowers that had come to the United Provinces from all points east, from Crete to Kurdistan. That was the secret of the tremendous variety they exhibited.
    Whether they were botanical species or cultivars, tulips could be grown from either seed or bulbs. Growing from seed is a chancy business; because plants grown from a single pinch of seed gathered from just one flower can exhibit considerable variation, it is impossible to know exactly what sort of tulip will emerge at the end of this time. Important details such as the color and the pattern of the flower can only be guessed at, which makes the process frustrating for anyone seeking consistency. And it takes six or seven years to produce a flowering bulb from seed, a very time-consuming process that must have seemed even more so in an age when the average life expectancy was not much more than forty years.
    Once a tulip grown from seed has matured and flowered, however, it can also reproduce itself by producing outgrowths known as
offsets
from its bulb. These are effectively clones of the mother bulb and will produce flowers that are identical to it. Offsets can be separated from the mother bulb by hand and, in another year or two, become bulbs capable of flowering themselves. From the point ofview of both the commercial grower—who seeks consistency—and the gardener—who prefers not to wait seven years to see a flower—propagation through offsets is infinitely preferable to raising tulips from seed. However, reliance on outgrowths does have one significant disadvantage: Most tulip bulbs will produce only two or three offsets a year and can do so for only a couple of years before the mother bulb becomes exhausted and dies.
    For this reason new varieties of tulips multiply only very slowly at first. Once a grower has identified, in a single flower of some new variety, great beauty or strength that he may be able to sell, he will have—even if all goes well—quite possibly only two bulbs the next year, four the year after that, eight in the next year, and sixteen in the fourth year of cultivation. If he parts with some of these bulbs, moreover, he limits his own ability to produce large quantities of the new variety. Plainly, then, it can take a decade for a new tulip to become available in any sort of numbers—and in Golden Age Holland,