146 



POPULAR HISTORY OP LICHENS. 



are scattered over the lacinise of the th alius in the form of 

 blackish or brownish point-like prominences, whose apices 

 under a lens exhibit pores or chink-like apertures; their 

 tissue is horny and dense, admitting of division into very 

 thin sections. The sterigmata are short, straight, narrow, 

 obtuse, and obscurely articulated ; the spermatia cylindrical, 

 straight, obtuse at the ends, and very transparent, generated 

 laterally from the sterigmata. The cavity of the spermo- 

 gone is divided into several convergent sinuses. The black- 

 punctate condition of the thalline lacinise has long been 

 familiar to lichenographers, but has usually been supposed 

 due to parasitic organisms^ and as such these spermogones 

 have been described by various authors as Spkseria Liclienum 

 or Endocarpon athallum. This is an excellent species in 

 which to study the form and development of the thecse 

 and spores, and the reaction of iodine thereon. In the 

 young state the thecse are elliptic- oblong, but when full 

 of spores they become broadly obovate, tapering suddenly 

 inferiorly into a narrow pedicle; they are comparatively 

 large, distinct, and are eight-spored."* The mature spores 



* For the minute anatomy of this species vide Von Holle, zur Entwicke- 

 lungsgeschi elite der Physcia ciliaris, Gottingen, 1849, and 'Botanische Zei- 

 tung/ July 25, 1851 ; and Dr. Speerschneider in the ' Botanische Zeitung,' 

 Oct. 7 and 14, 1853; Aug. 25, and Sept. 1 and 8, 1854. 



