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Montana Field Guide

Montana Field Guides

Granulating Rocktripe Lichen - Umbilicaria hirsuta

Species of Concern
Native Species

Global Rank: G2G4
State Rank: S1
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:

External Links

State Rank Reason (see State Rank above)
This species is apparently rare throughout its range in North America. In Montana it is known from one location.
General Description
Thallus foliose, umbilicate, roundish to somewhat lobed, mostly less than 6 cm in diameter, margins often turned under; upper surface gray to brown gray; lower surface pale gray, brown, or black, with pale to dark rhizines and somewhat platey; isidia lacking; soredia present, powdery, diffuse, near the margins; and apothecia rare (McCune and Geiser 2009).

Diagnostic Characteristics
This is the only sorediate species of Umbilicaria in North America. The soredia develop from disintegration of the upper cortex close to the margins. The soredia are often sparse and inconspicuous. A good search image is a pale brownish gray thallus (more like a Dermatocarpon than an Umbilicaria in color) and sheltered habitats, similar to U. americana and U. vellea, rather than the exposed habitats of many Umbilicaria species (McCune and Geiser 2009).

Range Comments
Arctic to California, Colorado, and Mexico; rare in the Pacific Northwest and Montana (McCune and Goward 2009).

On rock outcrops and siliceous rock where partially shaded. May be associated with seeps.

Reproductive Characteristics
Reproduces primarily asexually by soredia, but can reproduce sexually by spores from the apothecium.

Threats or Limiting Factors
None identified.

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Citation for data on this website:
Granulating Rocktripe Lichen — Umbilicaria hirsuta.  Montana Field Guide.  .  Retrieved on , from