lichens of the lower ozark region of missouri and arkansas

Apparently uncommon, on shaded hardwoods in dry to mesic sites. See comments under B.
schweinitzii.
Bacidia polychroa (Th. Fr.) Körb. [BACPO] - crustose
Occasional on lower and mid boles of a variety of deciduous trees, especially in mesic areas. This
species is very similar to B. diffracta except for the continuous, sometimes verruculose thallus, as
opposed to the granular thallus of B. diffracta.
Bacidia schweinitzii (Fr. ex E. Michener) A. Schneid. [BACSC] - crustose
Common and locally abundant on middle portions of tree boles in moist to dry mesic woodlands. This
is the most common member of the genus in the Lower Ozark region, and can be recognized in the field
by the thick, granular, dark green thallus and black apothecia, sometimes with a dull brown marginal
zone. Forms wi th brown or pale apothecia occur rarely in the area; these would key to B.
helicospora, but differ in the larger apothecia and better developed thallus.
Bacidia suffusa (Fr.) A. Schneid. [BACSU] - crustose
Common on shaded hardwood and Juniperus boles, often in mesic situations but occasionally in drier
sites. This species, B. diffusa, B. polychroa and B. schweinitzii can have pruinose apothecia, but B.
suffusa typically has a thicker thallus with more purplish brown tones in the apothecia.
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BACIDINA V�zda (Lecanoraceae)
Crustose lichens with thin grayish thalli and sessile, black, convex apothecia, thalline margin absent,
photobiont chlorococcoid(?), occurring in discrete aggregations (goniocysts) within the thallus, asci
Bacidia-type, with 8 hyaline, acicular, 3-7-septate spores; 2 species in the region.
1. Apothecia grayish to black; hypothecium reddish ................................B. egenula
1. Apothecia pale to orangish or brown; hypothecium hyaline .........................B. deli cata
Bacidina delicata (Larbal. ex Leight.) Coppins [BACDE] - crustose
Known only from a single collection from shaded sandstone in a Shannon County woodland.
Bacidina egenula (Nyl.) V�zda [BACEG] - crustose
Apparentl y uncommon in the Lower Ozarks, although common elsewhere in the Midwest, occurring
on calcareous substrates, especially in disturbed sites. Substrate s i nclude limestone, dolomite,
concrete, mortar, and bricks. This species is most common around towns, cities, and habitations. The
distinctive blue-green epithecium, acicular spores, and thin thallus are diagnostic.
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BUELLIA De Not. (Physciaceae)
Crustose lichens with well developed, continuous to areolate thalli and sessile black apothecia,
thal line margin usually absent at maturity, photobiont Trebouxia, asci Lecanora-type, with 8 brown,
ellipsoid to bacilliform, 1-3 septate spores; 6 species in the region. Reference: Imshaug (1951). The
following key includes several other lichens with two-celled brown ascospores that could be confused
with Buellia.
1. Apothecia lacking a thalline margin, the rim concolorous with the disk.
2. Thallus light gray, K+ yellow or red (stictic or norstictic acids).
3. Thallus corticolous.
4. Spores 15 �m long, >7 �m wide, with +/- acute apices ................ B. curtisii
3. Thallus saxicolous.