Allocetraria madreporiformis (aka “V-Fingers”)

Location Summary

Substrate: On calcareous soil.

Range: In arctic or alpine sites.

Identification Characteristics

Description: Thallus greenish yellow, dull but without pruina, with finger-like stalks branched dichotomously (in regular “Vs”) several times, 10-35 mm high, 1 – 2 mm thick, usually terete & erect, dimpled & ridged, occasionally somewhat flattened & more prostrate; branches filled with a dense, white medulla; cortex composed of palisade pseudoparenchyma.

Apothecia: Very rare, pale brown

Conidia: Thread-shaped, somewhat curved, & slightly broader at one end, 11 – 18 x 1 – 1.5 um.

Chemistry: Medulla PD-, K-, KC-, C- (protolichesterinic acid).

Lookalikes: This lichen is very similar to Dactylina, especially D. ramulosa, which often occurs as a neighbor.  Dactylina species are hollow, have lemon-shaped conidia, & lack fatty acids.  In D. ramulosa, the medulla is very webby & so the stalks are essentially hollow.  In addition, the branches are unevenly devided & usually heavily pruinose at the tips.

Bibliography: Lichens of North Amer5ica, by Brodo, Sharnoff, & Sharnoff

 

Database Entry:  Distance Everheart 12-26-13