Niebla testudinaria
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| Niebla testudinaria | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Lecanorales |
| Family: | Ramalinaceae |
| Genus: | Niebla |
| Species: | N. testudinaria |
| Binomial name | |
| Niebla testudinaria (Nyl.) Spjut (1996) | |
Niebla testudinaria is a fruticose lichen that grows on rocks along the foggy Pacific Coast of North America, from Marin County, California to just south of Tijuana in Baja California, in the Channel Islands (Santa Cruz Island) in California, and Isla San Martín[1] and Guadalupe Island in Baja California[2] The epithet, testudinaria given by William Nylander in 1870,[3] is probably in reference to the dilated branch with a reticulated surface, similar to a tortoise shell.
Niebla testudinaria is distinguished by a broad hemispherical thallus divided into many branches that spread widely above a narrow base where attached to a reddish orange pigmented holdfast, collectively appearing as a tangled mass to 7 cm high and 5 cm broad; the branches dividing frequently above base, more or less equal in length but often unequal in how they spread apart and in direction, often abruptly bent in changing direction of growth, especially the uppermost branches, often oblong to linear-prismatic[4] between branch intervals, frequently with dilated segments, asymmetrically elliptical in shape (bulging more on one side), occasional thalli with branches strongly flattened. The species (N. testudinaria) also recognized by the protruding reticulate vein-like ridges in the cortex as seen between branch margins, the cortex also appearing dull to slightly glossy along marginal ridges, relatively thick, 75–150 μm thick.[2] Pycnidia proment but often widely scattered.[2] Apothecia developing near ends of branches, solitary or in small aggregates. Divaricatic acid is the key lichen substances, with triterpenes.[2]
Similar species include Niebla homalea, Niebla eburnea, Niebla caespitosa, Niebla disrupta, and Niebla dissecta. The latter two (N. disrupta, N. dissecta) differ in having sekikaic acid.[2]
Niebla homalea is often difficult to distinguish from N. testudinaria. The key taxonomic character to recognizing N. homalea has been the obscure reticulate cortical ridges between the branch margins,[2] in which the obscurity appears related to an extra glossy layer above the normal two-layered cortex, referred to as an “epicortex”;[5] however, the more frequent development of transverse cracks also distinguishes N. homalea.[2] This may be related to a different developmental pattern in cortical hyphae. which is scarcely visible, except on Guadalupe Island where thalli have a glossy cortex with prominent transverse ridges less frequently cracked.[2] Additional character features for distinguishing N. homalea are branches that are mostly erect and closely parallel (“fastigiate”), and are often more curved than abruptly bent near apex. These features may also relate to the frequent transverse ridges, in contrast to the shorter reticulate hyphal ridges seen in thalli of N. testudinaria.[2]
Niebla caespitosa has a similar reticulate cortex to N. testudinaria but differs in its thickness, (25-)45–75 μm thick.[2] The thinner cortex in this species (N. caespitosa) is undoubtedly related to its crinkled margins, to the more sharply delineated cortical ridges, and to the more recessed cortical surface between the ridges.
Niebla eburnea differs in its pastry like smooth cortex, and in the branches twisted near base, in contrast to the frequent twisting of the longitudinal ridges as related to a change in the orientation of the branch margins in N. testudindaria[2]