[BGBM-Logo] Lichen determination keys
- neotropical lichinaceae genera -
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Key to genera of the Lichinaceae in tropical South America, excluding the Caribbean, by M. Schultz, December 1999

1a Thallus filamentous, mainly composed of the filamentous cyanobacterium Stigonema, trichomes 75-160 Ám thick, tips often with tiny side branches, aquatic on silicous rock, Guyana---Ephebe (brasiliensis)
1b Thallus not filamentous---2

2a Thallus foliose, lobes broad, rounded or strap-like---3
2b Thallus crustose, squamulose, umbilicate-rosette shaped or small fruticose---4

3a Thallus dark-grey, consisting of narrow, strap-like, richly branched lobes, apothecia immersed, small, discs pale yellowish-brown, on silicous rock in Mazaruni River, Guyana---Jenmania (goebelii)
3b Thallus dark reddish-brown, lobes rounded, 3-10 mm broad, folded, sparingly branched, on Granite inselberg, Guyana---Thyrea

4a Thallus small fruticose, forming tiny cushions, lobules cylindrical, 160-180(-200) Ám thick, sparingly branched, apothecia in apically tickened tips, on calcareous or silicous rock, Brazil, Venezuela---Synalissa (matogrossensis)
4b Thallus not small fruticose---5

5a Thallus squamulose, squamulose-umbilicate, umilicate-rosette shaped or consisting of elongated, slender, roundish lobes---6
5b Thallus crustose: film-like, effuse, areolate or effigurate---10

6a Thallus squamulose, attached by umbilicus, however, in surface view appearing as areolate crust; surface of squamules smooth, cracked with age, anatomy compact paraplectenchymatous, fungal cells small (2.5-5 Ám), in vertical rows, on quartzitic rock in Brazil and on Granite inselbergs in Venezuela---Phylliscidium (monophyllum)
6b Thallus different---7

7a Thallus of worm-like, straigth, bent or soigmoid lobes of -3 x 0.2-0.25 mm, lobes simple or divided into 2-3 lobules, vineacous-brown, apothecia sessile, base constricted, spores -16, small, globose 5(-7.5) Ám, axcus tips rounded, on Granite inselbergs in Venezuela and Guyana---Phylliscum ("vermiformis" ined.)
7b Thallus different---8

8a Thallus squamulose, small, 0.5-1 mm, surface of squamules smooth or rough, not tessellate---Phylliscum (macrosporum, tenue)
8b Thallus squamulose, umbilicate-rosette shaped, larger, squamules 1-4(-6) mm, their surface distinctly tessellate---9

9a Surface areoles very small, 60-120 Ám and marginal areoles not or indistinctly enlarged (-100 Ám) or surface areoles larger, 75-250 Ám and marginal areoles distinctly streched, 100-400 Ám, squamules roundish or irregular in outline---Paulia (gibbosa, myriocarpa)
9b Surface areoles small, 75-150 Ám, marginal areoles little streched, 100-250 Ám---Phylliscum (testudineum)

10a (5) Thallus with distinctly effigurate margins, marginal areoles -0.65 mm large, thallus black or dark brown-black, sometimes "isidia"-like outgrowths present on thalline surface, on Granite inselberg in Guyana and granitic coastal rock in Brazil---Pterygiopsis
10b Thallus not effigurate or indisticntly effigurate, marginal areoles <0.25 mm or not areolate at all---11

11a Thallus a thick crust, however, compound, of umbilicate squamules---Phylliscidium (monophyllum)
11b Thallus a real crust, thin or thick, areolate to effuse or film-like, attached to the substate by the whole lower surface---12

12a Photobiont a species of Rivulariaceae, thallus very thin, a film-like crust, gelatinous/slimy or granulose or of minute filaments, on wet calcareous or silicous rock, Paraguay, Brazil---Calotrichopsis
12b Photobiont never a species of Rivulariaceae, thallus crustose, but not slimy or of minute filaments---13

13a Anatomy loosely reticulate, algal cells usually large (>7.5 Ám), fungal cells elongated or roundish---14
13b Anatomy compact paraplectenchymatous, algal cells small (-7.5 Ám), fungal cells roundish---15

14a Thallus colour dark reddish-brown, sheath of algal cells reddish, KOH+ violett, paraphyses lacking, conidia large, sigmoid to falcate, >15 Ám long---Cryptothele
14b Thallus color dark olive-brown to blackish, sheath of algal cells yellowish-brown, KOH-, paraphyses present, true exciple thick, slightly coloured, hymenium devided by bands of sterile hyphae, on mortar, Rio de Janeiro---Leprocollema (americana)

15a Apothecial disc black, umbonate, immersed, true exciple blackish coloured, separated from thalline tissue by thin slit, thallus composed of tiny lobules that grow vertically and are dying from their base, on Granite inselbergs in Venezuela---Metamelanea (melambola)
15b Apothecia never umbonate and usually not black, true exciple never thick and blackish coloured---16

16a Thallus usually blackish, algal sheath yellowish-brown, KOH-, paraphyses not moniliform, asci thin-walled, not amyloid, cylindrical to narrow clavate, on silicous or calcareous rock---Psorotichia
16b Thallus dark reddish to dark reddish-brown, algal sheath usually reddish, KOH+ violett, paraphyses distinctly moniliform, asci thickwalled, with thin amyloid inner wall (sometimes not visible), clavate, on silicous or calcareous rock---Pyrenopsis


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