Sarcoglottis matogrossensis Engels & E.C.Smidt, 2021

Engels, Mathias Erich & Smidt, Eric De Camargo, 2021, A new Sarcoglottis (Orchidaceae: Spiranthinae) from the southern Brazilian Amazon, Phytotaxa 487 (2), pp. 171-176 : 172-175

Sarcoglottis matogrossensis Engels & E.C.Smidt sp. nov. ( Figs. 1–2 )

Type:— BRAZIL. Mato Grosso: Nova Canaã do Norte, Teles Pires River , UHE Colíder, 18 August 2018, [fl.], M . E . Engels , T . A . Silva & W . Monteiro 6617 (holotype MBM, isotype RB) .

Diagnosis:— The new species is morphologically similar to S. metallica but can be distinguished by the discolored-green leaves, that may or may not be variegated with white spots, flowering that occurs when the leaves have become senescent, and petals with apices conspicuously free, acute, and reflexed.

Description:— Humicolous and saxicolous, acaulescent herbs. Roots 2–5 mm long, appearing fasciculate, thick, cylindrical, hairy. Leaves 13.6–22.2 × 2.4–5.2 cm, narrowly elliptical to oblanceolate, discoloured-green, that may or may not be variegated with white spots, attenuating towards the base, margin entire, apex obtuse to acute. Inflorescence up to ca. 50 cm long, racemose, erect, 1–8-flowered; peduncle 19.2–40.9 × 0.3–0.5 cm, cylindrical, pubescent, greenish-brown; rachis 4.5–10.2 × 0.2–0.3 cm, cylindrical, pubescent, greenish-brown to brown; peduncle bracts 3.2–4.4 × 0.2–0.6 cm, narrowly triangular to narrowly elliptical, glabrous, greenish-brown, entire margin, acute apex; floral bracts 1.5–2.6 × 0.2–0.3 cm, narrowly lanceolate, glabrous, greenish-brown, entire margin, acute apex. Flowers resupinated; pedicellate ovary 2.8–3.2 × 0.4–0.6 cm, pubescent, green; dorsal sepal 1.4–1.7 × 0.3–0.4 cm, elliptical, concave, cuneate at base, margin entire, acute and recurved apex, pubescent adaxial face, light green with three darkergreen veins; lateral sepals 3.2–3.8 × 0.4–0.5 cm, falcate, decurrent in the ventral portion of the ovary, approximately 1/3 basal-connate, light green, pubescent adaxial face, portion free lanceolate, entire margin, acute apex; petals 1.2–1.4 × 0.2 cm, sub-sigmoid, elliptical in the general view, proximal margin internally adnate to the dorsal sepal in ca. 2/3 of the length, free proximal margin ciliated in ca. 2/3 of the length, acute apex, curved in a natural position, light green with three darker-green veins; lip 3.0–3.4 × 0.5–0.7 cm, spatulate in overview; narrowly oblanceolate, greenish-white; nectar glands ca. 0.5 cm long., narrowly ellipsoids, light green; apical lobe 4–5 × 5–7 mm, broadly oval, rounded base, entire margin, obtuse and apiculate apex, light green to yellowish-green with darker-green veins. Column 1–1.2 × 0.3 cm, flattened ventrally, glabrous, whitish; rostellum ca. 2 × 2 mm, sub-deltoid, truncated. Anther ca. 4 × 2 mm, elliptical, brownish-white. Stigma bilobed; elliptical, and confluent lobes; ca. 2 × 1 mm, whitish. Pollinarium with two elliptical-oblanceolate, whitish pollinia, ca. 4–5 × 1 mm; viscidium ca. 1 × 1 mm, transversely ellipsoid, dark brown. Fruits not seen.

Additional material examined (Paratypes):— BRAZIL. Mato Grosso: Colíder, 17 August 2017, [fl.], M . E . Engels 5666 ( MBM). Nova Canaã do Norte, Teles Pires River , UHE Colíder, 03 August 2019, [fl.], M . E . Engels 7338 ( MBM) .

Discussion: — The architecture of the inflorescence, shape of the leaves and floral morphology of S. matogrossensis are reminiscent of S. maroaënsis ( Romero-González et al. 2010: 514) , S. amazonica and S. metallica . However, it can be distinguished by the light green, discoloured leaves that may or may not be variegated with white spots (vs. reddish, brownish, or chocolate-purplish with irregular, bright green spots on the adaxial surface and homogeneously purplishred on the abaxial surface); the flowering which occurs after the senescence of the leaves (vs. fresh leaves present at flowering); and by the petals with apices conspicuously free, acute and reflexed (vs. adhering to the dorsal sepal nearly to the apex, obtuse, and straight). From S. maroaënsis specifically, it can also be distinguished by the glabrous lip (vs. rugose thickening near the apex of the apical lobe and extending to the apex of the central portion of the lip) and the apical lobe with an entire margin (vs. crenate and plicate).

With the recently described S. neillii ( Salazar et al. 2019) , S. matogrossensis shares the floral structure and predominantly green leaves. The latter can be easily distinguished by the narrowly elliptical to oblanceolate leaves (vs. elliptical to ovate) that are proportionally larger (13.6–22.2 vs. 5−13 cm long.), by the petals with apices conspicuously free, acute, and reflexed (vs. adherent internally to the dorsal sepal except at their little free recurved apices, obtuse and sometimes obscurely apiculate); and flowering occurs after the senescence of the leaves (vs. fresh leaves present at flowering).

Distribution, habitat, and phenology:— Sarcoglottis matogrossensis occurs as a saxicolous or humicolous plant in the stony soil and between the rocky outcrops of the understory of seasonal evergreen forest, in the Amazon Biome of the north-central region of the Mato Grosso state, at around 200–300 m of elevation. Flowering occurs during the dry season, in August and September.

Etymology:—The specific epithet refers to the Mato Grosso state, where the species was discovered.

Conservation status:—According to the IUCN (2017) criteria, Sarcoglottis matogrossensis qualifies as Data Deficient (DD). The two localities, where the new species was found, are separated by only ca. 30 km. The habitat is highly fragmented, and the two populations consist of less than ten individuals each. Deforestation and climate change are a major threat to Amazonian Biome ( Gomes et al. 2019). This is especially problematic in the Mato Grosso state, where the rate of illegal deforestation is very high. Recent reports suggest that between August 2016 and July 2017, illegal logging affected more than 60.000 hectares of forests ( Silgueiro et al. 2019). There are no studies of the impact on the herbaceous diversity, but without a forest canopy, the understory plants are likely threatened. Due to the low botanical coverage in the Mato Grosso state, further fieldwork is required to verify the presence of other populations of this species.

Figures

FIGURE 1. Sarcoglottis matogrossensis Engels & E.C. Smidt.—A. Habit of flowery, leafless individuals. B. Detail of the hairiness of the roots. C-D. Leaves. E. Detail of the venation of the leaves. F. Dorsal sepal. G. Petal. H. Lateral sepal. I. Lip. J–K. Column. J. Side view. K. Ventral view. L. Pollinarium. Drawn by M.E. Engels based on the type.

FIGURE 2. Sarcoglottis matogrossensis Engels & E.C.Smidt.—A. Habit of three leafless flowering individuals. B. Inflorescence. C. Flower in frontal view. D. Flower in oblique view. E. Flower in lateral view.F. Habit of leafy individuals, before flowering. G. Leaf adaxial and abaxial surfaces. Photos by M.E. Engels based on the type.