Cattleya porphyrascens E. L. F. Menezes, 2023

Menezes, Euler Da Luz Fernandes, 2023, Cattleya porphyrascens, a new species (Laeliinae) of the genus Cattleya is described for Minas Gerais State, Brazil, Phytotaxa 579 (1), pp. 61-66 : 62-64

Cattleya porphyrascens E. L. F. Menezes , sp. nov. ( Figures 1 and 2 A–M ).

Type:— BRAZIL. Minas Gerais: Diamantina, Sempre Vivas National Park , S 17° 57.0’ 36.2” W 43° 47’ 07.5”, 1,222 m a.s.l, October 10, 2018, saxicolous in rock crevices on rock field guarded by Poaceae grasses and rock, E.L.F. Menezes 69 (holotype: DIAM 8259!)

Cattleya porphyrascens is similar to C. haroldoi (V.P. Castro & E.L.F. Menezes) Van den Berg (2018: 2) , but differs from it by: the shape and length of the pseudobulb, obclavate elongated, 4.5–5.5 cm (vs. piriform, 2–3 cm, in C. haroldoi ); leaf length, 6–8 cm (vs. 3–4 cm); flowers on the stem, between 5 and 10 (vs. 2 to 4); the sub-circular shape of the flat lip (vs clearly oval); the four keels of the lip perfectly visible, straight and white (vs. orange, straight to the junction of the middle lobe, where they multiply and diverge); the length of the floral stem, 7–13 cm (vs. 5–8 cm); and by the truncated triangular profile of the column in side view (vs. rectangular). Cattleya porphyrascens also bears some resemblance to C. vandenbergii Fraga & Borges (2008: 21) , but differs from it by: pseudobulb length 4.5–5.5 cm (vs. 2.5–3.5 cm); longer leaf length, between 6–8 cm (vs. 5–6 cm); the angled arrangement of the leaves in relation to the pseudobulb (vs. aligned); 4 keels well-separated and perfectly visible (vs. the 2 internal keels of the lip partially fused with the external ones, and barely visible in the extension that runs from the base of the lip to the junction of the middle lobe); the truncated triangular profile of the column in side view (vs. falcate); isthmus of the lip inexistent (vs. patent and with an extension of between 1 and 2 mm); the temporal isolation of flowering that occurs at the end of the austral winter and beginning of spring (vs. flowering in the late austral summer and early autumn).

Description:— Plant saxicolous, cespitose, 7–12 cm tall. Rhizome short. Roots white, glabrous, flexible, 0.2–0.3 cm diameter. Pseudobulbs obclavate, articulated, 2 internodes, smooth, reddish green, 4–5 × 1–1.2 cm, with scarious amplexicaul sheaths that disintegrate with time, unifoliate. Leaves elliptic, lanceolate, retroflexed, coriaceous, fleshy, concave, apex acute, green with purple tinge, 6–8 × 1.0– 1.5 cm. Spathe linear, apex oblique, 2–3 × 0.4–0.5 cm. Inflorescence semi-recurved from the apex of the pseudobulbs, from within the spathe, 7–13 cm long, floral bracts elliptic and embracing the stem and the base of the pedicel, with 5–10 flowers. Flowers purple-violet, 2.5–3.5 cm in natural diameter; sepals and petals violaceous, labellum white centrally over the disc and onto the midlobe region, gradually becoming dark violet towards the distal margins, margins very dark violet. Sepals spreading; dorsal sepal elliptic, apex acute, 1–2 × 0.5–0.6 cm; lateral sepals oblong-lanceolate, 1.5–2.0 × 0.4–0.6 cm. Petals elliptic, slightly reflexed, 1–2 × 0.3–0.4 cm. Labellum three-lobed, circular when flattened, 1–1.2 × 1–1.2 cm, isthmus obscure, 4 longitudinal lamellae, proportionally wide, sulcate, white, starting from the base of the labellum, the two external lamellae extend to the junction of the lateral lobes and the two central ones extend to the center of the median lobe. Lateral lobes semi-elliptic, 0.8–0.9 × 0.4–0.5 cm. Median lobe narrow in natural position, margins sinuous, emarginate, oblong-rectangular when flattened, 0.4–0.5 × 0.4–0.5 cm. Pedicel green, 2.5–3.5 × 0.2–0.3 cm, ovary purple-black. Column semicircular in dissection, curved, 0.5–0.6 × 0.3–0.4 cm wide. Stigmatic cavity triangular, 0.25–0.3 cm in diameter. Anther helmet-shaped, white, 0.4–0.5 cm wide. Pollinia 8, irregularly shaped, 0.4 mm long, yellow, typical of the genus.

Distribution and Ecology:— The species proposed here was found in the Sempre Vivas National Park in a population of approximately 200 individuals with a saxicolous habit and dispersed over a large area of rock outcrops. The plants were small, between 7–12 cm tall, growing in rock fissures, or among species of Cactaceae or species of other plant families. The plants were always growing in locations not exposed to direct sunlight for any prolonged period of time, being protected by cracks in the rocks or by companion vegetation such as the grasses (seen in Figure 1 ) or other low plants. The floral stems of the orchids were semi-pendant with up to 6–10 flowers ( Figure 1 ) having uniform violaceous tones. Observed flowering between September and October in the southern hemisphere.

Etymology:— Named for the striking purple-violet color of its flowers.

Taxonomic Discussion: — Cattleya porphyrascens is a member of the group of species with saxicolous habits that share the same basic characteristics of small plants, small flowers, and relatively short floral stems. The new species shares similarities with C. haroldoi , but with sufficient morphological differences to separate them. The new species has an evidently longer floral stem (in relation to the height of the plant) which maintains the flowers above the leaves and more visible to potential pollinators amid the low vegetation, with its normally associated segments being narrower but the labellum wider, labellum disc dark purple and keels the only white structures, the labellum is circular when flattened, its middle lobe oblong-rectangular. In C. haroldoi , the labellum disc is entirely purple and the keels are strong orange to light yellow. The ecological niches occupied by the two species also separate them, as C. porphyrascens is always reasonably protected from direct sunlight ( Figure 1 ) while C. haroldoi grows fully exposed.

In relation to C. vandenbergii , C. porphyrascens is a larger plant, its leaves are positioned at an angle to the pseudobulb (vs. aligned in C. vandenbergii ), the floral stem is longer, the four keels of the labellum disc are separate and perfectly visible (vs. while the two inner keels being partially fused with the outer ones), the disc is uniformly dark purple (vs. lavender with light pink areas), and the middle lobe is rectangular (vs. oval).

A comparative table of C. porphyrascens and the related species C. haroldoi and C. vandenbergii , as well as comparisons of the morphologies of the flattened lips and flowers are presented below ( Table 1 , Figure 4 ).

Figures

FIGURE 1. Cattleya porphyrascens in its grass-shaded habitat.

FIGURE 2. Cattleya porphyrascens. A. Habit. B. Front view. C. Profile. D, Rear view. E. Peduncle. F. Petals and sepals. G. Entire labellum flattened. H. Labellum dissected. I. Median lobe. J. View of the white lamella. K. Column, ventral view, dorsal, and side profile. L. Anther. M. Pollinia. Photographs by Mauro Sergio Rosim based on the Holotype.

FIGURE 4. Dissected flowers and morphology of the labella. A. Cattleya porphyrascens—circular. B. Cattleya haroldoi—oval. C. Cattleya vandenbergii—circular.