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SPERMOGONIA 205
He also regards as macrospores those of the pycnidia of Calicium tra-
chelinum which Moller was able to germinate so successfully, and all the
more so as they were brownish in colour, true microspores or spermatia
being colourless.
Miiller 1 has recorded some observations on the pycnidia and stylospores
of the Strigulaceae, a family of tropical lichens inhabiting the leaves of
the higher plants. On the thallus of Strigula elegans var. tremula from
Madagascar and from India, he found pycnidia with stylospores of abnormal
dimensions measuring 18-26/4 in length and 3 /A in width, and with I to 7
cross septa. In Strigula complanata var. genuina the stylospores were 2-8-
septate and varied from 7-65 /* in length, some of the spores being thus
ten times longer than others, while the width remained the same. Miiller
considers that in these cases the stylospore has already grown to a septate
hypha while in the pycnidium. As in the pycnidiospores, described later
by Hedlund, the spores had germinated by increase in length followed by
septation.
The spermogonia of Strigula, which are exactly similar to the pycnidia
in size and structure, produce spermatia, measuring about 3/4 x 2/*, and it is
suggested by Miiller that the stylospores may represent merely an advanced
stage of development of these spermatia. Both organs were constantly
associated on the same thallus ; but whereas the spermogonia were abundant
on the younger part of the thallus at the periphery, they were almost
entirely replaced by pycnidia on the older portions near the centre, only
a very few spermogonia (presumably younger pycnidial stages) being found
in that region.
Lindsay 2 has described a great many different lichen pycnidia, but in
many instances he must have been dealing with species of the "Fungi imperfecti"
that were growing in association with the scattered granules of
crustaceous lichens. There are many fungi Discomycetes and Pyreno-
mycetes parasitic on lichen thalli, and he has, in some cases, undoubtedly
been describing their secondary pycnidial form of fruit, which indeed may
appear far more frequently than the more perfect ascigerous form, and might
easily be mistaken for the pycnidial fructification of the lichen.
G. GENERAL SURVEY
a. SEXUAL OR ASEXUAL. It has been necessary to give the preceding
detailed account of these various structures pycnidia or spermogonia in
view of the extreme importance attached to them as the possible male
organs of the lichen plant, and, in giving the results obtained by different
workers, the terminology employed by each one has been adopted as far as
1 Miiller 1885.
2
Lindsay 1859 and 1872.