PART 1

2. Ascomata scattered; clypeus large (0.5-0.7 mm), flat to hemispherical,
(depending on erosion of surrounding limestone), often with a distinct
papilla; thallus endolithic, white; ascospores 17-22(-24) × 9-11 µm;
Monroe County (Key West) ............................................................................. V. riddleana R. C. Harris
1. Ascomata sessile or with base immersed in thallus or limestone; black
clypeus hemispherical; ascomatal wall colorless or dark.......................................................................... 3
3. Ascospores larger, 15-30 × (7-)9-16 µm; thallus endolithic or
epilithic; ascomata 0.35-0.6 mm diam. ................................................................................................. 4
4. Thallus white, endolithic or epilithic ................................................................................................... 5
5. Exciple dark; clypeus not broadly spreading; ascomata
0.4-0.5 mm diam.; ostiolar area depressed; ascospores
21-30 × 11-14 µm; Dade and Monroe counties.................................. Verrucaria sp. Britton 870
5. Exciple pale; clypeus spreading, 0.5-0.6 mm diam.;
ascospores 2-28 × 10.5-14.5 µm; Dade and
Monroe counties................................................................................ Verrucaria sp. Thaxter 397
4. Thallus green gray or olive green to brown green............................................................................. 6
6. Ascospores 15-23 × (7-)9-11 µm; thallus olive or brown
green, areolate; ascomata 0.35-0.4 mm diam.; Taylor
County ................................................................................................ Verrucaria sp. Buck 24842
6. Ascospores 23-27 × 11-12.5 µm; thallus green gray, rimose
or areolate; ascomata ca. 0.4 mm diam.; Taylor and
Wakulla counties ................................................................................ Verrucaria sp. Buck 18979
3. Ascospores small, 9-16 × 4-6.5 µm; thallus epilithic, tan to brown;
ascomata 0.25-0.3 mm diam. ............................................................................................................... 7
7. Ascospores 9-12 × (4-)5-5.5(-6.5) µm; exciple usually dark;
Dade, Hillsborough and Monroe counties .............................................. Verrucaria sp. Buck 22655
7. Ascospores 13-16 × 5.5-6.5 µm; exciple pale;
Dade County............................................................................................ Verrucaria sp. Britton 741
NOTES
There is so little known about subtropical/tropical Verrucaria that I have not ventured to describe any new
taxa. Only three species have Caribbean types and I have seen material of only one of these. One could
shoehorn some of the Florida taxa into European species, i.e., Britton 870 into V. muralis Ach. or Thaxter 397
into V. calkinsiana Servít, but in my present state of ignorance it doesn't seem worth it. This has obviously
been the practice in the West Indies.
Verrucaria riddleana R. C. Harris, nom. nov.
Verrucaria mamillaris Riddle in Britton & Millspaugh, Bahama fl. 522. 1920 (non Hepp in Zollinger,
1854). Type. BAHAMAS. Watling's Island: vicinity of Cockburn Town, 13 Mar 1917, Britton &
Millspaugh 6130, not seen.
New to North America. I have not seen the type collection but two "paratypes" agree with the Florida
material. It is no surprise to find a species desribed from the Bahamas on Key West. I have no recent
collections. FLORIDA. Monroe County: Key West, Feb 1898, Thaxter 395, 420, s.n. (NY).
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