474 i Flora Unveiled
also indisputable that cryptogams had an additional stage based on the asexual production
of spores. The problem was that neither angiosperms nor gymnosperms seemed to produce
spores, suggesting that they lacked an asexual stage of the life cycle.
The history of the discovery of sex in plants had come full circle. Seed plants, once
believed to be entirely asexual, were now thought to reproduce exclusively by sexual
reproduction. Only the cryptogams seemed to have a true asexual stage in their life
cycles. Both conceptually and biologically, the presence of an asexual, spore- producing
stage in cryptogams suggested a profound taxonomic divide between the cryptogams
and seed plants. Yet cryptogams and seed plants were supposed to belong to the same
plant kingdom. The stage was now set for Wilhelm Hofmeister to unveil the asexual
stage of the seed plant life cycle, revealing the unity of the life cycles of the cryptogams
and seed plants.
Notes- Charpa, U. (2003), Matthias Jakob Schleiden (1804– 1881): The history of Jewish interest
in science and the methodology of microscopic botany. Aleph 3:213– 245; Farley, John (1982),
Gametes and Spores. Johns Hopkins University Press, p. 48. - https:// de.wikipedia.org/ wiki/ Johann_ Horkel.
- Charpa, Matthias Jakob Schleiden.
- Schleiden, M. J. (1849/ 2013), Principles of Scientific Botany, or Botany as an Inductive
Science. Forgotten Books, pp. 310– 311. - Cited by Roberts, H. F. (1929), Plant Hybridization Before Mendel, Princeton University
Press, p. 161. - Idem., p. 162
- von Gaertner, C. F. (1849), Experiments and Observations on the Production of Hybrids in
the Plant Kingdom (Versuche und Beobachtungen über die Bastarderzeugung im Pflanzenreich);
see Roberts, Plant Hybridization Before Mendel, p. 168. - Mendel, G. (1865/ 66), Experiments on Plant Hybrids, trans. Eva R. Sherwood. In C. Stern,
ed., The Origin of Genetics: A Mendel Source Book. W. H. Freeman and Company. - Fungi were grouped in the plant kingdom in most biology textbooks until 1969, when
Robert Whittaker argued for placing them into a separate Kingdom. The new “Five Kingdom
System” included the Monera, Fungi, Protista, Plantae, and Animalia. - Online Oxford English Dictionary.
- Hedwig called the protonema a “cotyledon.” The term cotyledon (from the Greek
word kotulēdōn meaning cup- shaped cavity) was first applied to a patch of villi on the pla-
centa of mammals in the mid sixteenth century. Linnaeus was the first to apply the term
to the specialized leaves of embryos that act as absorptive organs, which take up nutrients
from the endosperm like a placenta, rather than act as storage organs (Philosophia Botanica,
1751). The term later came to be applied to the primary leaves or “seed leaves” of the embryos
of seeds plants. - Both archegonia and antheridia are present in algae, bryophytes, ferns, and fern allies,
whereas archegonia (but not antheridia) are also found in most gymnosperms. - Morton, A. G. (1981), History of Botanical Science. Academic Press.