Parmelia pseudotenuirima Gyeln.
P. tenuirima f. isidiosa Müll. Arg., Bull. Herb. Boissier 4: 90 (1896).
Thallus orbicular, closely attached, 7-17 cm diam., corticolous. Lobes moderately to relatively broad, 4-8(-20) mm wide, apices subrotund, margins entire, ± sinuous. Upper surface smooth, shining towards margins, pale grey to dark brownish-grey, pseudocyphellae laminal, moderate, small, punctiform or curved, developing from elevated maculae, isidiate. Isidia developing directly from the upper cortex or along the edges of pseudocyphellae and cracks, delicate, cylindrical, ± richly branched and occasionally forming a dense mat over the surface of older lobes. Lower surface black or dark brown, paler at margins, moderately rhizinate with a pale marginal zone devoid of rhizines and papillae. Rhizines black, simple or sparingly branched. Apothecia occasional to rare, sessile, to 10 mm diam., disc concave to plane, dark brown, matt or slightly shining, margins thin, concave to plane, dark brown, matt or slightly shining, margins thin, crenate, isidiate or not. Ascospores ellipsoid, 14-18 × 7-9 µm. Chemistry: Cortex K+ yellow; medulla K+ yellow → red, C-, KC+ red, Pd+ orange. Salazinic and lobaric acids and atranorin.
N: Rather rarely collected from coastal sites north of Auckland.
Australasian
P. pseudotenuirima closely resembles P. saxatilis in that both species have pseudocyphellae and isidia. However P. saxatilis is closely rhizinate to the margins with rhizines often projecting beyond the margins. Commonly the margins of the lower surface are paler but this paler zone is rhizinate or papillate even to the extremities. In contrast, the lower surface of P. pseudotenuirima has a much broader, pale, marginal zone which is smooth and completely devoid of rhizines and papillae. At the margins of the upper surface of P. saxatilis there is generally a ± well-developed pale, whitish reticulum of maculae. This reticulum is normally absent in P. pseudotenuirima. Isidia in P. saxatilis develop from well-defined, elongate maculate ridges on the upper surface (cf. soralia in P. sulcata) whereas the isidiate maculae of P. pseudotenuirima are generally punctiform or irregularly extended or curved. Rhizines in P. saxatilis are generally much denser and more slender and richly branched than those of P. pseudotenuirima. P. pseudotenuirima is obligately corticolous while P. saxatilis successfully colonises rock as well as bark.
