240 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
fluent—in the latter case becoming very irregular inform. Their colour is usually 
brown; that of the thallus varies between olive and gray. The spermogones are 
generally most conspicuous on the gray thallus, from the contrast of their deep 
olive-brown colour. The apex of the spermogone is usually brown, sometimes 
blackish, the ostiole being minute and very indistinctly marked. Sometimes it is 
elongated or chink-like. The apices of confiuent spermogones are generallystudded 
over with minute black or brown roundish ostioles. The interior tissue is grayish, 
and of a horny denseness; it is hence easily sectioned in thin lamine. The 
sterigmata are longish, and composed of short, roundish cellules; they are the 
“ Minnliche Prosphysen” of the speculative Bayruorrer. So abundant and so 
constant are the spermogones sometimes, as to give a character to the plant; 
hence spermogoniferous states have been described as varieties by the earlier 
authors. Such is the var. melanostigma of Acharius. 
Although it is only a few years ago since ITz1GsoHN pointed out the existence of 
what are now called ‘‘spermatia,” yet the spermogones above described have long 
been familiar to lichenologists. So long ago as 1741, DitLentus* drew attention 
to the brown tubercles occurring on the thallus of P. ciliaris ; and Hepwie,+ in 
1784, saw in the same bodies one of the forms of his supposed masculine organs 
of reproduction in lichens. AcHARIuS regarded the same organs as secondary or 
accessory apothecia,—of inferior importance to the normal or usual ones,—which 
he called Cephalodia, and which he described as filled with gongyli. Nor did 
IrziGsoun, so lately as 1850, correctly appreciate the character of the spermogones 
of P. ciliaris, or of their contents. He described the spermogones as antheridia, 
and the spermatia as spermatozoids, similar to those of Marchantia and Poly- 
trichum, possessing true animalcular movements. From these spermatozoids, 
however, the spermatia of P. ciliaris differ entirely in regard to their genesis. 
The important bearing of IrzicsoHn’s observations, whether his theories were 
correct or not, was at once seen by other Continental botanists, who forthwith 
proceeded to repeat his experiments. Some observers corroborated ITzicsoun’s 
theories as well as his facts; while others, more cautious, less biassed, and less 
impulsive or sanguine in their temperament perhaps, saw the spermatia, but 
took a different view as to their nature and analogies. It is unnecessary to detail 
the results of the observations of different German botanists, who contributed 
voluminously on the subject to the “ Botanische Zeitung,” in 1850 and 1851. t 
Suffice it to notice the most important result of IrzigsoHn’s observation on 
P. ciliaris,—apparently a most simple one,—which was, that the subject was 
followed up in France by TuLAsneE to a previously unknown extent. He made an 
* Historia Muscorum, p. 150, Tab. 20, f. 45, BC. 
{ Theoria Generationis et Fructificationis Plant. Crypt., p. 120. Pl. 30 and 31. 
t Vide vol. viii., pp. 393-94, May 17, 1850; pp. 917-19, December 27, 1850. Vol. ix., 
pp. 153-4, February 21, 1851, and p. 913. 

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