332 i Flora Unveiled
In this charming passage, Grew was merely echoing classical writers, but he ended his
discussion with a teaser. In addition to its two “secondary” uses, Grew proposed that the
Attire also had a “Primary and Private Use,” beneficial to the plant itself. But on this subject
Grew was not yet prepared to speculate: “[W] hat may be the Primary and Private Use of the
Attire ... I now determine not.”^23 Grew’s circumspection about the function of the Attire
suggests that, in 1671, he may already have been thinking about the possible sexual role of
stamens, but was waiting for confirmation of some kind before discussing it openly.
Precisely when Grew developed his sexual theory of plants is difficult to say. One of his
inspirations, which he noted in his 1676 paper on flowers, was the discovery of hermaph-
rodism in snails. Although there has been some confusion in the literature about priority,
there now seems little doubt that the discovery of hermaphrodism in snails was originally
made by Grew’s colleague at the Royal Society, the British naturalist John Ray, in 1660.^24 In
his first book, describing new plant species growing around Cambridge, Ray noted that the
deadly nightshade plant was susceptible to snails and slugs despite the plant’s lethal effects
on humans. He went on to add:
In passing one may mention that they [snails] are hermaphrodite. That they alter-
nately function as male and female by impregnating and receiving at the same time
will be clear to anyone who separates them as they are having intercourse in Spring,
although neither Aristotle nor any other writer on Natural History has recorded this
fact.^25The Dutch anatomist Jan Swammerdam confirmed Ray’s observations and published
them in his Historia Insectorum Generalis (The Natural History of Insects) in 1669.
Several factors probably contributed to Grew’s decision to announce his new sexual theory in
- The discovery of hermaphrodism in snails had, by this time, established a solid precedent
that made hermaphrodism in plants seem less radical. Malpighi’s first installment of Anatome
Plantarum published in 1675 had failed even to mention the phenomenon, and Grew may have
sensed that this was an opportune time to step out from under Malpighi’s shadow. At the same
time, he may have worried that, as a junior scientist, challenging the eminent Malpighi’s one-
sex model of flowers might raise some eyebrows. This may account for his private conversation
with Sir Thomas Millington, the first physician to William and Mary and a prominent mem-
ber of the Royal Society. He may have sought out Sir Thomas as a sounding board for his ideas.
Grew’s diffidence is on display in his description of their meeting:
In discourse hereof with our Learned Sedleian Professor Sir Thomas Millington, he
told me, he conceived, That the Attire doth serve as the Male, for the Generation
of the Seed. I immediately reply’d, That I was of the same Opinion; and gave him
some reasons for it, and answered some Objections, which might oppose them. But
withall, in regard every Plant is hermaphroditic, or Male and Female, that I was also
of Opinion, That it serveth for the separation of some parts, as well as the Affusion
of others.^26Historians generally have taken a skeptical view of Millington’s contribution to the
sexual theory of plants. Other than Grew’s comment, there are no written records of Sir
Thomas’s views on the subject.^27 Moreover, Grew’s contemporary, the great British botanist