Keys to the macrolichens and checklist of the lichens and ...

2a. Thallus truly isidiate or with small, finger-like or clavate extensions..................... 3
2b. Thallus erose- or pustulate-sorediate ....................................................................... 5
3a. Lobes inflated, up to 5 mm wide; perforations confined to the lower cortex and to
the upper cortex on lateral lobes or extensions; upper surface with patches of
narrow, true, solid isidia which leave pits when shed...............................M. isidiata
3b. Lobes not inflated, not exceeding 2.5 mm wide; perforations present in the upper
cortex; hollow, finger-like or clavate extensions often present ............................... 4
4a. Upper cortex weakly striate-ridged to roughened; lobes often becoming pendulous,
pale grey; isidia elongat ...........................................................................M. pendula
4b. Upper cortex smooth; lobes closely appressed, at least partly glossy brown; isidia
elongate.............................................................................................. M. digitiformis
4c. Upper cortex smooth; lobes closely appressed; isidia globose........M. globoisidiata
5a. Upper cortex fragile, finely wrinkled, dissolving into ± effuse soredia; soralia
laminal, becoming ±erose and confluent; usually containing barbatic acid, in
addtlion to the stictic acid complex ....................................................... M. dissoluta
5b. Upper cortex firm, smooth or only faintly wrinkled, not dissolving into soredia;
soralia or pustules delimited, often ± elevated; not containing barbatic acid; stictic
acid complex present................................................................................................ 6
6a. Lobes inflated, not or sparingly branched, up to 5 mm wide; perforations confined
to the lower cortex and to the upper cortex on lateral lobes or extensions; soralia
scattered, often marginal, labriform or erumpent with markedly uneven, lacerate
margins...............................................................................................M. efflorescens
6b. Lobes not inflated, short or only somewhat elongate, often richly branched, up to
2.5 mm wide, upper cortex perforate; soralia or pustules sparse or abundant,
usually formed on short, lateral lobe extensions...................................................... 7
7a. Thallus closely appressed; lobes in part pale yellowish, suffused brown to nearly
black; soralia capitate, confined to central parts of the thallus, originating from
marginal lobules; saxicolous....................................................................M. saxicola
7b. Thallus not closely appressed; lobes not brown; soralia not capitate; rarely
saxicolous................................................................................................................. 8
8a. Thallus with fatty acids........................................................................M. faminensis
8b. Thallus with stictic acid complex .............M. malesiana and/or (or =) M. subsimilis
8c. Thallus with fumarprotocetraric acid.............................................M. menyamyensis
9a. Lobes inflated, sparingly branched; perforations restricted to lateral lobes or
extensions on the upper cortex, present or nearly absent on the lower cortex....... 10
9b. Lobes not inflated, usually richly branched; perforations present only on the upper
cortex...................................................................................................................... 11
10a. Lobes sparingly irregularly branched, up to 5 mm wide; perforations confined to
the lower cortex and to the upper cortex of lateral lobes or extensions; lobes
greyish, rarely brown or black-maculate; apothecia rather frequent; usually
epiphytic; containing stictic acid complex.......................................M. megathallina