548 L)R LAUDER LINDSAY ON NEW LICHENICOLOUS MICRO-FUNGI. 



less, oval sporidia of the Usnea. No hymen ial tissue, asci, nor paraphyses can be 

 made out, even under iodine ; which, however, produces in some places only a 

 blue reaction in the medullary tissue of the Usnea. The structure of the spermo- 

 gones of the Usnea is described and figured in my "Memoir on Spermogones" 

 (p. 122, plate iv. figs. 2-5). This parasite has certain points of resemblance, espe- 

 cially as regards the sporidia, to Phymatopsis dubia, Linds., and Abrothallus Usnew, 

 Rabenh., as I have described and figured them in my " Otago Lichens and Fungi " 

 (p. 442, et seq., plate xxx. figs. 36-41). 



15. On sterile thallus of Parmelia per la ta y L.; India, M. C. Cooke, 1866; ordinary 

 a-ciliate form of the Parmelia as it occurs, from Britain, Norway, New Zealand, 

 and the Canary Islands, in my Herbarium. In what appears to be its highest 

 stage of growth, the parasite occurs as sub-rotund or sub-difform, raised, sub- 

 convex, black maculse, with a granulate irregular surface. In the young state it 

 is developed as punctiform or papillseform bodies, sometimes girt with a ragged 

 thalline margin. In the young state the body is wholly immersed in the thallus 

 of the host or nearly so, while in age it emerges and becomes epithalline. In 

 none of its stages of growth does the parasite show sporidia or other reproductive 

 structure. 



16. Associated with Verrucaria Taylori, Carr., and Opegrapha vulgala, Ach.; 

 corticolous ; Dunscombes Wood, Cork, Carroll. Perithecia contain sporidia that 

 are brown, 3-septate, bulging opposite each septum ; 00083" long, and 00033" 

 broad. 



17. On thallus of Lecidea Hookeri, Schser. (sub-nom. L. spherica, Schser.) in 

 his Exsic. No. 526. The thalline squamules are dotted over with small, black, 

 prominent papillae, externally resembling spermogonia, but containing sac-shaped 

 asci, and 1-septate, colourless, ellipsoid sporidia, somewhat resembling those of 

 some forms of Verrucaria epidermidis. The same thallus bears the parasitic 

 Sphoeria Hookeri, Nyl. (Prod. 175 and 139; Linds. "Otago Lich. and Fungi," p. 

 438)* with verrucarioid perithecia, and deep brown, 3-septate sporidia, 001" 



* Two specimens of S. Hookeri (sub-nom. Verrucaria), which I examined in the Kew Herbarium, 

 had the following characters fe— 



1. Summit of Ben Lawers. Thallus Parmelioid, pale yellowish-white. Perithecia are quit 

 those of a Verrucaria ; seldom, however, forming regular cones or papilla; more usually flattened and 

 irregular as to form and size. None of the hymenial elements give blue with iodine. SSporidia 

 broadly ellipsoid, tapering suddenly at the tips ; 3-septate ; becoming by longitudinal sub-division of 

 the loculi sub-muriform ; deep brown ; 'OOP' long, 0005'' broad. 



2. Gemmi, Switzerland. Perithecia much larger and ostioles more distinct ; immersed or semi- 

 immersed ; bursting through the cortical layer of thallus, with — at least usually at first, in their 

 young state — stellate Assuring. Thallus here again Parmelioid and simple ; usually buff-coloured, 

 sometimes pale green. The plant has an Endocarpoid facies. 



In both cases the perithecia occur by themselves on a thallus, which appears to belong to them. 

 It seems to me that it is the same plant that occurs sometimes with a proper thallus {Verrucaria), 

 and at other times as an athalline parasite (Sphoeria); that it has equal claims to rank as a Splucria 

 or Verrucaria ; and that it matters little whether it is classed among the Sphairiai or Verrucaria — 

 fungi or lichens — provided only fungologists and lichenologists would come to some common under- 

 standing regarding it ! 



