PDF - CES (IISc)

SPERMOGONIA 193
B. SPERMOGONIA AS MALE ORGANS
Interest in these minute "tubercles" and their enclosed "corpuscles"
was revived by Itzigsohn 1 who examined them with an improved microscope.
He macerated in water during a few days that part of the thallus on which
they were developed, and, at the end of the time, discovered that the
solution contained large numbers of motile bodies which he naturally took
to be the corpuscles from the broken down tubercles. He claimed to have
established their function as male motile cells or spermatozoa. The discovery
seemed not only to prove their sexual nature, but to link up the reproduction
of lichens with that of the higher cryptogams. The tubercles in which the
"
spermatozoa " were produced he designated as antheridia. More prolonged
maceration of the tissue to the very verge of decay yielded still larger numbers
of the "
spermatozoa " which we now recognize to have been motile bacilli.
Tulasne 2 next took up the subject, and failing to find the motile cells,
he wrongly insisted that Itzigsohn had been misled by mere Brownian
movement, but at the same time he accepted the theory that the minute
conceptacles were spermogonia or male organs of lichens. He also pointed
out that their constant occurrence on the thallus of practically every species
of lichen, and their definite form, though with considerable variation, rendered
it impossible to regard them as accidental or of no importance to the life of
the plant.
He compared them with fungal pycnidia such as Phyllosticta or
Septoria which outwardly they resembled, but whereas the pycnidial spores
germinated freely, the spermatia of the spermogonia, as far as his experience
went, were incapable of germination.
C. OCCURRENCE AND DISTRIBUTION
a. RELATION TO THALLUS AND APOTHECIA. We owe to Tulasne 3 the
first comparative study of lichen spermogonia. He described not only
their outward form, but their minute structure, in a considerable number
4
of representative species. A few years later Lindsay published a memoir
dealing with the spermogonia of the larger foliose and fruticose lichens, and,
in a second paper, he embodied the results of his study of an equally ex-
tensive selection of crustaceous species. Lindsay's work is unfortunately
somewhat damaged by faulty determination of the lichens he examined, and
by lack of the necessary discrimination between one thallus and another of
associated and intermingled species. Both memoirs contain, however, much
valuable information as to the forms of spermogonia, with their spermatio-
phores and spermatia, and as to their distribution over the lichen thallus.
Though spermogonia are mostly found associated with apothecia, yet
1
Itzigsohn 1850.
- Tulasne 1851.
3 Tulasne 1852.
4
Lindsay 1859 and 1872.
S. L. 13