' =o. eer 
340 CYCLOCARPINEE {LECANIA 
in the ascus (4-16 in L. syringea), colourless, more or less 
elongate and rather narrow, |-3-septate. Spermogones with 
pleurogenous or acrogenous arcuate or straight spermatia. 
Lecania, as here understood, includes not only Lecania but 
Placolecania A. Zahlbr., which has a more distinctly squamulose- 
effigurate thallus and pleurogenous spermatia. The apothecia in 
several of the species lose the thalline margin at an early stage, and 
look like Biatorine. 
Thallus more or less squamulose............ § i. PLACOLECANIA. 
Thallus variously crustaceous................ § ii. HULECANIA. 
§ i. PLaAcoLEecaANIA Stein. in 8S. B. Akad. Wiss. Wien. Math.- 
Nat. Cl. evii. Abth. i. p. 106 (1898).—Thallus squainulose, the 
squamules effigurate at the circumference, imbricate, or becoming 
granular. 
1. L. candicans A. Zahlbr. in Oesterr. Bot. Zeitschr. lv. p. 61 
(1905).—Thallus orbicular, adnate, squamulose, continuous or 
lobed or cracked-areolate in the centre, plicate-lobate at the 
circumference, glaucous- or greyish-white, often pruinose (K —). 
Apothecia rather small, about 1 mm. across, the dise brownish- 
black, more or less pruinose, the thalline margin entire, per- 
sistent ; paraphyses slender, wider and brown at the tips ; spores 
fusiform-ellipsoid, 1-septate, 7-14 p long, 4-7 p thick.—Lichen 
candicans Dicks. Pl. Crypt. fase. ii. p. 15, t. 9, fig. 5 (1793) ; 
With. Arr. ed. 3, iv. p. 17; Engl. Bot. t. 1778. L. epigeus 
Ach. Lich. Suec. Prodr. p. 105 (1798) (non Pers.). Lecanora 
epigea Ach. Lich. Univ. p. 422 (1810) ; Hook. FI. Scot. ii. p. 50. 
L. candicans Scher. Enum. p. 59 (1850); Cromb. in Grevillea 
xviii. p. 46 & Monogr. i. p. 390. Placodium epigeum 8S. F. Gray 
Nat. Arr. i. p. 446 (1821) (non Pers.).. Pl. candicans Dub. 
Bot. Gall. p. 661 (1830); Mudd Man. p. 133; Cromb. Lich. 
Brit. p. 46; Leight. Lich. Fl. p. 178; ed. 3, p. 164. Squamaria 
candicans Hook. in Sm. Engl. FI. v. p. 195 (1833) pro parte. 
Easicc. Johns. n. 411 ; Leight. n. 218. 
Placed recently in the genus Placolecania by Zahlbruckner because 
of the squamulose thallus ; it isa very well-marked lichen which could 
only be confused with Buwellia canescens, from which, however, it can 
be distinguished by the marginate apothecia and by the absence of 
reaction with potash. The apothecia are generally abundant, but the 
spores are rarely formed or are very imperfect. 
Hab. On calcareous or cretaceous rocks in maritime and inland 
districts.—Distr. Here and there in England; rare in N. Wales and 
W. Scotland, not seen from Ireland.—Z. M. Portland Island and 
Swanage, Dorset; near Beachy Head, Sussex; Weston-super-Mare, 
Cleeve Hill and Bathampton Downs, Somerset; Malvern, Worcester- 
shire; Buxton and near Cromford, Derbyshire; Llanymynech Hill, 
Shropshire ; Great Orme’s Head, Carnarvonshire; Anglesea; Tees- 
dale and Egglestone, Durham; Arnbarrow and Helsington, West- 
moreland; near Shean Ferry, Argyll. 
