Ramalina subcalcarata V. Marcano & A. Morales, 2021

Marcano, Vicente, Méndez, Antonio Morales & Prü, Ernesto Palacios, 2021, The genus Ramalina Acharius (Ascomycota, Lecanoromycetes, Ramalinaceae) in northern South America, Phytotaxa 504 (1), pp. 1-77 : 58-60

4. Ramalina subcalcarata V. Marcano & A. Morales sp. nov.; Mycobank #838607 (Fig. 38)

Thallus corticolus, ramificatione subdichotomo. Rami generaliter cavi sed saepe in parte compressi, subtus perforati, perforationibus coalescentibus. Soralia nulla. Apothecia terminalia. Sporae ellipsoideae. Acida usnicum, homosekikaicum, sekikaicum, boninicum, succinprotocetraricum, protocetraricum et fumarprotocetraricum continens.

Type:― VENEZUELA. Miranda: Los Guayabitos , 1200–1400 m, 1 January 1957, Vareschi 6173 (holotype VEN) .

Thallus corticolous, fistulose, 1–2.5 cm high, subdichotomously and intricately branched.Branches hollow and inflated, dorsiventral, 1–4 mm wide, with perforations on the lower side, smooth or rarely longitudinally grooved. Soralia not seen. Medullary layer dense, continuous, often with embedded strands of chondroid tissue in part originating from the disintegrating lower side. Pycnidia not seen. Apothecia common, terminal on main branches and on short branches, spurred, disc flat or convex, 0.5–3 mm in diameter, reddish brown; epithecium 8–9 µm thick; hymenium 34–40 µm thick; hypothecium 20–30 µm thick. Ascospores, 1–septate, colorless, short ellipsoid, 8–12 x 3–4 µm.

Chemistry ( TLC, HPTLC): Strain 1. Homosekikaic, sekikaic, boninic, hypoprotocetraric, succinprotocetraric, protocetraric and fumarprotocetraric (tr.) acids (Vareschi 6173). Strain 2. Homosekikaic, sekikaic, boninic, succinprotocetraric (tr.), protocetraric (tr.) and fumarprotocetraric acids (Vareschi 6207–B).

Ecology and distribution: Ramalina subcalcarata is known only from the type locality, where it grows on shrubs in a moist forest at 1200–1400 m.

Remarks: Ramalina subcalcarata is very similar to R. calcarata and R. pusiola ( Krog & Swinscow 1974) . However, R. calcarata contains divaricatic acid, and R. pusiola sekikaic acid, whereas R. subcalcarata lacks divaricatic acid and contains substances in both the sekikaic acid complex and the the protocetraric acid complex. Further, R. subcalcarata has short ellipsoid spores (8–12 x 3–4 µm) whereas R. calcarata and R. pusiola have long ellipsoid spores (12–15 x 5–7 µm). SEM shows that the thallus of R. subcalcarata has a central cavity and a smooth, slightly sinuose upper surface (Fig. 18), as well as crystals of a lichen substance (probably usnic acid). The cross-section shows an outer cortex and an inner medullary tissue, with a deposition of crystals of lichen substances on the medullary hypha-walls (Fig. 21). The ellipsoid spores have a smooth epispore.

The name of this species refers to its similarity to R. calcarata .

Adittional specimens examined: VENEZUELA: Miranda: 8 January 1956, Vareschi 6207–B ( VEN) .