PART 1

2. Lirellae black or white pruinose, not pigmented .................................................................................... 3
3. Lirellae sessile, black, shiny, not pruinose .......................................................................................... 4
4. Ascospores rounded at one or both ends ....................................................................................... 5
5. Lirellae smaller, short, fusiform or once branched, rarely asteriform ..........................................6
6. Hymenium not inspersed; ascospores 13-15 × 4-5 µm;
south to Manatee County .....................................................................................O. atra Pers.
6. Hymenium inspersed; disk exposed; ascospores
13-15 × 4-4.5 µm; Duval County ................................................. Opegrapha sp. Calkins 604
5. Lirellae coarse, elongate, branched; ascospores 13-15 × 4-5 µm;
Collier, Dade and Duval counties .............................................................. O. candida Müll. Arg.
4. Ascospores tapering at both ends, 18-19 ×
4-4.5 µm; lirellae small; disk not exposed;
Okeechobee and Polk counties ...........................................................Opegrapha sp. Britton 819
3. Lirellae initially immersed in bark of Taxodium; disk a strongly flexuose
slit becoming quite broadly exposed; margin thick, black or densely white
pruinose; ascospores 25-28 × 4-5 µm, cells ± equal; Franklin and Liberty
counties ......................................................................................................... O. cypressi R. C. Harris
2. Lirellae encrusted with bright orange pigment, short, straight;
ascospores 17-20 × 4 µm; Collier County ................................................... O. aurantiaca B. de Lesd.
1. Ascospores 6-14-celled............................................................................................................................. 7
7. Growing on bark or wood ...................................................................................................................... 8
8. Disk not covered by dense white layer .............................................................................................. 9
9. Disk broadly expanded, red brown.............................................................................................. 10
10. Ascospores 5-8-celled, 16-20 × 4-5 µm; lirellae long, flexuose,
branched; margin not carbonized below hymenium; south to
Polk County ....................................................................................... O. longissima Müll. Arg.
10. Ascospores 9-12-celled, 38-50 × 4 µm; lirellae short, orbicular
or elongate and strongly flexuose; margin carbonized below
hymenium; Dade County...................................................................Opegrapha sp. Britton 2
9. Disk hidden or if exposed, then black ......................................................................................... 11
11. Ascospores 6-celled; lirellae fusiform or once branched ...................................................... 12
12. Ascospores narrow, 3-4 µm wide; disk hidden................................................................. 13
13. Thallus whitish, continuous or rimose,
sometimes scanty; ascospores 24-30 × 3-4 µm;
south to Polk County ............................................................................ O. vulgata Ach.
13. Thallus white, thick, matte, almost byssoid;
6