opeoraphaJ graphidace^ 239 



16. 0. varia Pers. in Ust. Ann. Jiot. vii. p. 30 (1794).— 

 Thallus effuse, whitish, pulverulent, thin. Apothecia prominent, 

 black, sessile, roundish-oblong, elliptical, or elongate, often 

 attenuate at each end ; the margins prominent, rather thin and 

 inflexed or often disappearing ; the disc forming a narrow slit or 

 dilated and plane, sometimes almost convex ; hypothecium dark- 

 brown ; paraphyses slender, wavy and branched, involved above 

 in a brown mucilage ; spores irregularly ovate-fusiform, usually 

 5-septate, colourless or becoming brownish, rather large, 0,020-30 

 mm. long, 0,007-9 mm. thick. — Hook, in Sm. Engl. ¥1. v. p. 145 

 (excl. syn. 0. liclienoides and 0. notJia) ; Tayl. in Mackay Fl. 

 Hib. ii. p. 106 (excl. syn. Engl. Bot. t. 1890 & 0. 7ioiha) ; 

 Leight. in Ann. Mag. Nat. Hist, ser, 2, xiii, p. 94, t. 5, f. 9 

 (1854) (inch vars. pulicaris Fr. Lich. Eur. p. 364 (1831), 

 diaphora Fr. I. c. p. 365, tigrina Schter. Enum. p. 157 (1850) k 

 iridens Schser. /. c. p. 158) & Lich. Fl. p. 381 ; ed. 3, p. 404 (inch 

 ff. pulicaris, diaphora, tigrina and tridens) ; Mudd Man. p. 229 

 (inch vars. pulicaris, signata (Fr. /. c), tigrina f. tridens Mudd 

 & diaphora) ; Cromb. Lich. Brit. p. 97 pro parte. O. diaphora 

 Ach. Meth. p. 19 (1803); Engl. Bot. t. 2280; O. signata var. 

 tigrina Ach. Lich. Univ. p. 262 (1810). Lichen scripfusYSir. puli- 

 caris Lightf. Fl. Scot. ii. p. 801 (1777). L. pulicaris Hoffm. Enum. 

 Lich. p. 14, t. 3, f. 2, f. (1784)? L. diaphorus Ach. Lich. Suec. 

 Prodr. p. 20 (1798). L. signaius Ach. /. c. p. 23. Alyxoria 

 diaphora S. F. Gray Nat. Arr. i. p. 504 (1821). 



Exsicc. Mudd n. 205 ; Leight. n. 287 (as 0. varia, var. 

 tigrina). 



A very variable species in the form and size of the apothecia, 

 giving rise to numerous varieties which appear to be only forms or 

 stages of growth that are frequently represented side by side on the 

 same specimen. When the apothecia are rather small with the ends 

 rounded or tapering and the margins persistent and incurved, it is 

 f. pulicaris ; the apothecia are more elongate and obtuse in f. tigrina, 

 while in f. diaphora the margins tend to disappear, the disc becoming 

 rather wide and flat or slightly convex. Usually the apothecia are 

 simple, straight or bent and numerous, lying in all directions, some- 

 times they are stellately arranged (f. tridens). 



Lichen pulicaris Hoffm., though professedly based on Light- 

 foot's variety, is doubtful and incomplete both in description and 

 figure. Some recent lichenologists have rejected the name varia, 

 substituting as species 0. pulicaris, 0. diaphora and 0. notha. The 

 microscopic characters of the apothecia are alike in all ; in 0. dia- 

 phora the spermatia are slightl}' shorter and thicker, 0,003-4 mm. 

 long, 0,002 mm. thick ; in O. pulicaris they are 0.004 mm. long and 

 0,001 mm. thick {fide Nyl. Lich. Par. pp. 104-5 (1896)). 



Hah. On trees. — Distr. Common in England and the Channel 

 Islands, rarer in Scotland and Ireland. — B. M. Jersey ; Appuldur- 

 combe, I. of Wight ; Lustleigh, Devon ; New Forest, Hants ; near 

 Shermanbury, Gravely, Wiston, Wakehurst Park, and St. Leonards, 

 Sussex; Canterbury, Kent; Eeigate, Surrey; near Millhill, Middle- 

 sex; Quendon and Ulting, Essex; Hollybush Hill, Malvern, Little 



