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unprepossessing prothallus— a completely separate individual— that constitutes the sexual
generation of the fern. Such an alien life cycle violates all our expectations about how sex
works, and that is why it is so hard to understand and accept.
We have the same false expectations of flowering plants. When we look at a glamorous
rose bush, we assume it is the sexual stage of the life cycle. After all, aren’t the stamens and
pistils of the flowers the “sexual organs” of the rose, just as Nehemiah Grew, Camerarius,
Sébastien Vaillant, Linnaeus, Erasmus Darwin, Joseph Koelreuter, and all the other sexual-
ists said they were? In fact, they’re not.
And when we turn over rose leaves and find no spores there, doesn’t that demonstrate
that roses do not make spores? No, it doesn’t! The blossoming rose bush with its gorgeous
hues and seductive fragrance is not the sexual stage of the rose life cycle. It is the asexual
spore- producing stage, comparable to the mature fiddlehead fern plant.
The fundamental difference between ferns and rose bushes is that we can see the
spores of a mature fern plant on the undersides of its leaves, while the spores of the rose
bush are concealed within the anthers and ovaries of the flower, which are actually mod-
ified leaves. Otherwise, the fiddlehead fern and the rose share the same basic life cycle.
The hidden spores within the anthers and ovaries develop into the true sexual stages of
the rose, the male and female gametophytes, more commonly known as the pollen tube
and the embryo sac.
This was Wilhelm Hofmeister’s brilliant insight, which he elaborated in his Theory of the
Alternation of Generations. Though hardly a household name, Hofmeister has been justifi-
ably called “one of the true giants in the history of biology ... [one who] belongs in the same
pantheon as Darwin and Mendel.”^6Hofmeister’s Theory of Alternation of Generations
Wilhelm Hofmeister was born in Leipzig, in 1824, the son of Friedrich Hofmeister, a music
bookseller and occasional publisher, and his second wife Frederike. He had no formal
schooling beyond that of a vocational high school. Originally destined to take over the fam-
ily business, he served as an unpaid apprentice between the ages of fifteen and seventeen
at a music store in Hamburg. This position apparently left him with sufficient free time to
indulge his interest in natural history, sparked by his father who was an amateur botanist.
Upon returning to Leipzig in 1841, he became increasingly fascinated by botany, inspired
by Schleiden’s new textbook. While working at his father’s bookshop, he began a series of
microscope investigations into the life histories of plants, usually carried out between four
and six in the morning prior to opening the store.
Hofmeister was extremely nearsighted, but this handicap served him well as a morpholo-
gist. Severe myopics have the ability to focus on objects placed very close to their eyes, and
the closer an object is to the eye the greater the magnification of the object displayed on the
retina.^7 As pointed out by Kaplan and Cooke,^8 Hofmeister’s myopia made it possible for
him to observe the minutiae of living material with extraordinary clarity:Because Hofmeister had to bring living specimens so close to his unaided eyes, he
became incredibly skilled at making hand sections through living material and mak-
ing, for example, the most detailed observations on embryo development.^9