Ramalina venezuelensis 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 : 67-68

5. Ramalina venezuelensis V. Marcano & A. Morales sp. nov.; Mycobank #838610 ( Fig. 40 )

Thallus corticolus, erectus. Laciniae intricate ramulosae, canaliculatae, pseudocyphelliis linearibus instructis. Pycnidia non visa.

Apothecia subterminalia et lateralia vel terminalia et apicalia. Sporae ellipsoideae. Acida usnicum et psoromicum continens. Type:― VENEZUELA. Amazonas: Cerro La Neblina , 1850 m, 3 December 1984, L. Brako 7702 (holotype VEN, isotype NY) .

Thallus corticolous, erect, up to 3 cm long, tufted, originated from a holdfast, densely dichotomously branched. Branches pale green or pale yellow, subshiny, canaliculate to subcanaliculate, 0.9–1.5 µm broad, with dense, thin, secondary branches. Pseudocyphellae laminal or marginal, linear. Soralia not seen. Cortex paraplectenchymatous, 245–290 µm thick, of thick walled hyphae, peripheral chondroid tissue forming continuous layers, 155–175 µm thick, medulla dense. Pycnidia not seen. Apothecia subterminal and lateral or terminal and apical, long-spurred; disc convex to concave, up to 5 mm diameter; epithecium (8–)10–12 µm thick; hymenium (28–)40–50 µm thick; hypothecium (30–)40–60 µm thick. Ascospores 1–septate, ellipsoid, straight, elongate or strongly curved, 9–11 x (3.6–)4–4.5 µm.

Chemistry (TLC, HPTLC): Strain 1. Psoromic acid (Brako 7702; Vareschi 5198). Strain 2. Nil (Vareschi 5199; Dennis 2345).

Ecology and distribution: Ramalina venezuelensis has a wide distribution in Venezuela, where it grows on shrubs in moist rainforests at 1800–2000 m. It is known only from Venezuela.

Remarks: Ramalina venezuelensis is very similar to R. stenospora and R. cumanensis . It differs from R. stenospora in having canaliculate branches, with dense secondary branching, ellipsoid spores and psoromic acid as medullary compound. Ramalina stenospora , by contrast, has flat branches, fusiform spores, lacks secondary branching, and contains stenosporic acid. Ramalina cumanensis , by comparison, has marginal pseudocyphellae, long ellipsoid spores (10–14 µm) and lacks lichen substances. In Colombia and Venezuela, R. reducta , R. tenuissima and R. venezuelensis are the only Ramalina species containing psoromic acid. Under the SEM, R. venezuelensis shows a complanate thallus, with marginal pseudocyphellae (Figs. 14 and 15); the absence of soredia; a slightly smooth upper surface; diffuse, small, pore-like perforations (Fig. 14); variable cottony hyphae covered by a thin layer of secreted material (Fig. 20); a scabrose apothecial surface; and allantoid or curved spores.

The name of the species refers to the type locality.

Additional specimens examined: VENEZUELA: Dto. Federal: National Park El Avila, Dennis 2345 (K, VEN) ; Mérida: Valle Santo Domingo, near Las Piedras , 2000 m, 5 August 1956, Vareschi 5199 ( VEN) ; Quebrada del Río Santo Domingo, near Las Piedras , 2000 m, 5 August 1956, Vareschi 5198 ( VEN) ;

Figures

FIGURE 40. Ramalina venezuelensis. Habit (holotype). Scale = 7.13 mm.