X93 



A NEW MARINE LICHEN. 



By George Massee. 



i 



(Plate 324.) 



The following interesting addition to our Lichen-flora occurred 

 amongst a small collection of marine Lichens, handed over to me 

 for identification by Mr. E. A. L. Batters, by whom they were 

 collected : — 



Verrucaria laetevirens, sp. n. Thallus forming a broadly 

 effused, rather thick, inseparable film, very smooth and even, not 

 cracked, rather gelatinous, bright olive green, the lobed margin 

 paler and yellowish ; gonidia protococcoid, globose, 12-15 fi diam. ; 

 perithecia minute, crowded, globose, entire, black, completely 

 immersed in the thallus, ostiolum forming a very minute, slightly 

 raised black ring; asci clavate, spores 8, inordinate, 1-celled, 

 elliptical, colourless, 11-12 x 6 /x; paraphyses scanty, slender, 

 cylindrical; spermogonia immersed, mixed with the apothecia, 

 sterigmata filiform, simple, aseptate, spermatia cylindrical, straight, 

 8-9 x 2 /i. 



Hab. On smooth rocks between tide-marks. Berwick-on- 

 Tweed and Burnmouth, on the east coast ; Loch Goil, Cumbrae, 

 and Gare Loch, on the west. 



There are at least sixteen British marine Lichens included 

 under the somewhat heterogeneous collection called Verrucaria. 

 The present species is distinguished amongst these by its broadly 

 expanded, perfectly smooth, bright green thallus, presence of para- 

 physes, and form of sterigmata and spermatia. Its nearest ally is 

 V. microsporioides Nyl. 



Plate 324, fig. 1, portion of Verrucaria later irem, nat. size; fig. 2, section 

 through thaUus and apothecium, x 300 ; fig. 3, section through apermogonium, 

 X 300 ; fig. 4, section of portion of thallus, x 400 ; fig. 5, isolated gonidia, 

 X 400; fig. 6, sterigmata and spermatia, x 400; fig. 9, asci, paraphyses, and 

 spores, x 400. 



V. marina (Deak.) Leight. This rare species, first observed by 

 Dr. Deakin on submerged maritime rocks at Meadfoot, near 



Torquay, was collected by Mr. Batters at Berwick-on-Tweed and 

 Loch Goil. An examination of Deakin's type-specimen, now in the 

 Leighton collection in Kew Herbarium, shows the spores to be 

 elliptic-oblong, 3-septate at maturity, 9-10 x 3-4 /x ; paraphyses 

 absent. Thallus smooth, not becoming cracked, very dark olive- 

 green, margin blackish. 



Plate 324, fig. 8, ascus and spores of Verrucaria marina, x 400. 



V. mucosa Whlngb. This species closely resembles V. latevirens 

 when examined under a pocket-lens, but is usually darker in colour, 

 and differs materially in the absence of paraphyses and smaller 



gonidia. Loch Goil. 



V. maura Whlngb. The present species is not uncommon on 

 rocks between tide-marks, and is readily known by the black thallus 

 becoming minutely cracked in an areolate manner when dry, and 



Journal of Botany.— Vol. 30. [July, 1892.] o 



