Heterodermia follmannii (Sipman)

Jung, Patrick, Werner, Lina, Briegel-Williams, Laura, Emrich, Dina & Lakatos, Michael, 2023, Roccellinastrum, Cenozosia and Heterodermia: Ecology and phylogeny of fog lichens and their photobionts from the coastal Atacama Desert, MycoKeys 98, pp. 317-348 : 317

Heterodermia follmannii (Sipman)

Fig. 2

Description.

Thalli up to 5 cm, only attached at central parts by whitish to brown rhizines, which are significantly thinner and shorter than the cilia. Thallus divided into linear, ca. 2-4 mm wide, often dichotomously or palmately branched, ascending, often bullate lobes. Upper side flat or slightly convex to concave; lower side decorticate, without rhizines, ca. 0.8-1.3 mm wide, bordered by rather swollen thallus margins, sometimes with weak and irregular cartilaginous ridges. Internodes ca. 1-1.5 mm long. Cilia are conspicuous and dense, ca 3 or more per mm on each side, black, usually up to 5 mm long, mostly simple, occasionally with a few terminal bifurcations or a few perpendicular branchlets. The cilia are not very strictly marginal, and may be implanted more or less away from the margin, on the lower, lateral, or upper side of the margin, or on the upper surface, incidentally also on ridges of the lower side. Soredia present, farinose, produced in slightly greenish or blue greenish soralia on the lower side of upturned lobe tips. Soralia poorly delimited and perhaps covering all of the lower surface of the lobes, but most distinct near the lobe tips. In cross section with a cortical layer of very irregular thickness, forming pronounced longitudinal ridges, ca 25-40 µm thick on thin spots, up to 100-150 µm at the ridges, with ca. 100 µm thick medulla. Apothecia and pycnidia unknown. Trebouxioid photobionts are arranged in a continuous layer.

Secondary metabolites.

Atranorin, zeorin, weak traces probably of additional terpenoids. Cortex UV-, C-, K+ yellow, KC-, P-; medulla UV-, C-, K-, P-.

Distribution and ecology.

The species grows attached to stones or epiphytically on the lower third of cacti restricted to a small strip on top of the steep coastal ridge with high wind speeds and regular fog events. It is also known from the neighborhood of Iquique ( Follmann 1994; Alto Patache personal observation), near the coast in northern Chile. Here it grows on SW-facing slopes between ca. 600-1300 m, on low vegetation or directly on soil, in desert vegetation with increased precipitation by fog. Often appears together with H. adunca .

Notes.

Heterodermia follmannii is morphologically indistinguishable from H. multiciliata except by its lobes with upturned tips and sorediate lower side, and by the absence of apothecia. The great morphological similarity suggests that it is a vegetatively reproducing species derived from H. multiciliata . It may be most easily confused with H. comosa , which shares the regularly branched, ascending lobes which are sorediate on the lower surface. H. comosa differs by its flabellate-expanded, not linear lobes, and its usually white cilia, which are exceptionally darkened at the tips. According to the three-gen phylogenetic reconstruction presented here the species falls within the monophyletic Leucodermia cluster and is separated from H. adunca . According to the ITS-only phylogeny the species falls in a separated cluster together with H. adunca , one H. leucomelaena and one H. erinacea ITS sequence.

Specimen examined.

specimen HBG-025794 (Herbarium Hamburgense, Hamburg, Germany) from Chile, Atacama Desert, Pan de Azúcar National Park.

Figures

Figure 2. Heterodermia follmannii A, B photographs of Heterodermia follmannii with its gray thallus and black cilia C top view of thallus lobes D bottom view of thallus lobes without lower cortex showing the white, loose medulla and brownish attachment sides E cross section of thallus lobe showing the photobiont layer and the gray upper cortex which forms a rim on the ventral side with an open medulla F ventral side of thallus lobe with open medulla and black, long and branched cilia G top view H upwards bent terminal thallus part which is slightly bloated I ventral view of the attachment side. QR code redirects to 3 D scan of Heterodermia follmannii. PW: Lichen.