Catasetum × sheyllae Krahl, Cantuária & J.B.F.Silva, 2021

Cantuária, Patrick De Castro, Krahl, Dayse Raiane Passos, Krahl, Amauri Herbert, Chiron, Guy & Silva, João Batista Fernandes Da, 2021, Catasetum × sheyllae (Orchidaceae: Catasetinae), a new natural hybrid from Brazilian Amazon, Phytotaxa 527 (4), pp. 257-265 : 259-262

Catasetum × sheyllae Krahl, Cantuária & J.B.F.Silva nothosp. nov.

Type:— BRAZIL. Pará: Aveiro, Mamuru River, epiphyte in Igapó , 3°14’20.41”S; 56°33’17.51”W, 11 m, 03 September 2020, J. B. F. da Silva 5488 (holotype INPA; Figs. 2 , 3 , 4 , 5A–C ) .

A natural hybrid between C. boyi and C. garnettianum with intermediate morphological features. It is characterized by the trilobed lip with two small triangular and erect calluses at the base of the lateral lobes, semi-oval and laciniate lateral lobes, an ovate-oblong median lobe with sparsely denticulate margins, and a small, dentiform, acute callus Epiphytic, cespitose plant. Rhizome short, inconspicuous. Pseudobulb fusiform, 6.8–14.5 × 1.9–2.7 cm, 6–7-leaved, covered by leaf sheaths. Leaves oblanceolate, 28.6–51.2 × 4.4–6.6 cm, membranous, plicate, prominently 5–7-veined, margin entire, base constricted, acute. Male inflorescence basal, 24.2–27.1 cm long, racemose, 11–14-flowers, first erect then arched due to the weight of the flowers; peduncle cylindrical, green, becoming purple towards apex; floral bract lanceolate, 0.9–1.1 × 0.4–0.5 cm, concave, purplish-green, margin entire, apex acute. Female inflorescence basal, 18.2–22.5 cm long, racemose, 4–5-flowers; peduncle cylindrical, greenish; floral bract ovate, 1.0–1.2 × 0.7–0.8 cm, concave, greenish, margin entire, apex acute. Male flowers with petals and sepals greenish with deep brownish spots and lip brownish outside and whitish inside, resupinate; pedicel 2.8–3.2 cm long, cylindrical, erect, purplish; dorsal sepal lanceolate, 3.0–3.3 × 0.9–1.0 cm, concave, symmetrical, margin entire, acute; lateral sepals lanceolate, 3.0–3.3 × 1.0– 1.1 cm, concave, symmetrical, margin entire, involute, apex acute; petals elliptic, 2.6–2.8 × 0.6–0.7 cm, symmetrical, margin entire, apex acute; lip trilobed, 1.3–1.4 × 0.7–0.9 cm, with a saccate near the base, sac 0.4–0.5 cm deep, rounded, with two small calli at the base of the lateral lobes, calli 0.1–0.2 cm high, triangular, erect, acute; lateral lobes semi-ovate, 0.5–0.7 × 0.5–0.6 cm, erect, margin laciniate, median lobe ovate-oblong, 0.6–0.8 × 0.3–0.4 cm, margin sparsely dentate, apex acute with a small apical, tooth-shaped, acute, callus 0.1–0.2 cm high; column subtriangular, 1.9–2.1 cm long, fleshy, rostrate, contracted at base, brownish; rostellum 0.3–0.4 cm long, brownish; antennae 0.6–0.7 cm long, symmetrical, parallel to convergent, projected towards the bottom of the lip saccus; anther 0.8–0.9 cm long, purplish; anther cap 0.8–1.0 cm long, rostrate; viscidium 0.1–0.2 × 0.1–0.15 cm long, whitish; stipe 0.2–0.3 × 0.1 cm long, laminar, rolled, yellowish; pollinia 2, obovate, 0.3–0.4 × 0.1–0.2 cm, hard, compressed, yellowish. Female flowers greenish-yellow with brownish spots on the sepals and petals, resupinate; pedicel 3.0– 3.3 cm long, cylindrical, arched; sepals lanceolate, symmetrical, margin entire, apex acute, the dorsal sepal 2.0–2.2 × 0.7–0.8 cm, the lateral sepals 2.1–2.3 × 0.8–1.0 cm, with involute margins; petals elliptic, 2.0–2.2 × 0.8–0.9 cm, symmetrical, apically acute; lip globular, 2.0–2.2 × 1.9–2.1 cm, 1.0– 1.2 cm deep, entire, striated inside, margin entire and thick, apex acute; column rounded, 2.8–3.0 cm long, fleshy, shortly rostrate, greenish; stigma 0.2–0.3 cm long, viscous. Fruit not seen.

Etymology: —The specific epithet is a tribute to the Brazilian pharmacist Sheylla Susan Moreira da Silva de Almeida, who has contributed to the studies of new bioactive molecules for multiple uses, and recently began to do prospective studies on Catasetinae .

Distribution and habitat: —This new natural hybrid has been collected on a fallen phorophyte in an anthropized forest de igapó (floodplain) having suffered fire damage, on the river Mamuru in the municipality of Aveiro, PA, Brazil. Given that part of this river also runs in the Amazonas state we think that the taxon should also occur there. The putative parent species has also been observed in this area (see more below).

According to Petini-Benelli (2020), C. boyi is distributed to the states of Amazonas and Pará. It has been registered to occur in the municipality of Aveiro on the basis of material collected by one of the present authors (J.B.F. da Silva) and deposited at MG (151046). Meanwhile, according to Petini-Benelli (2020) C. garnettianum has restricted distribution to the state of Amazonas. However, its occurrence in Pará is also confirmed on the basis of material collected by one of the present authors (J.B.F. da Silva) in the municipality of Aveiro and deposited at MG (198317). The occurrence of putative parental species is therefore confirmed for the municipality where the new natural hybrid was found.

Phenology and floral visitors: —the flowering time of the new taxon occurs from June to August. As for the putative parental species, both can be observed flowering during the first half of the year, mainly between the months of April and June; between April and May for C. boyi and between February and June for C. garnettianum (personal observations by A.H. Krahl and J.B.F. da Silva). Thus, the flowering times of the taxa overlap at least partly in the area of the study, making the cross-pollination possible.

Male bees of belonging to the genus Euglossa spp. (Euglossini) are the main floral visitors of the parental species (personal observations by J.B.F. da Silva). These bees appear to visit the flowers in order to collect volatile compounds present in the lip.

Morphological affinities: —the new entity presents a morphology that is intermediate between that of the two putative parents, C. boyi and C. garnettianum ( Table 1 ). Vegetatively, Catasetum species are practically indistinguishable ( Holst 1999, Walker-Larsen & Harder 2000). However, the new nothospecies has large pseudobulbs similar to those of C. boyi , rather than the short pseudobulbs reported for C. garnettianum ( Petini-Benelli 2020) . The leaves of C. × sheyllae are oblanceolate, as in C. boyi , rather than oblong-lanceolate as in C. garnettianum ( Petini-Benelli 2020) . The most notorious features of C. × sheyllae lie in the male flowers. The elliptic petals and lanceolate sepals are similar to those of C. garnettianum , whereas the lip is trilobed, as in C. boyi , rather than entire. The lip has a rounded sac as in C. boyi and shows the same small triangular erect acute calli at the base of both lateral lobes. The lateral lobes are ovate and erect (as in C. boyi ) but their margins are laciniate. They are more similar to those of C. garnettianum , which has sparsely ciliate margin, rather than the denticulate margin of the lateral lobes with obliquely rising teeth seen in C. boyi . The median lobe is ovate as in C. boyi and oblong as in C. garnettianum . The margin of the new taxon is sparsely dentate as in C. garnettianum (margins sparsely ciliate) and shows a small tooth-like callus at apex, probably inherited from C. garnettianum that has a prominent callus at the lip apex ( Rolfe 1888, Mansfeld 1930, Petini-Benelli 2020, table 1). The antennas are parallel and directed towards the center (parallel to convergent), as in C. boyi ( Petini-Benelli 2020) .

Figures

FIGURE 2. Catasetum × sheyllae. A. Habit. B–D. Flower. E. Perianth. F. Lip. G. Lip, longitudinal section. H–J. Column. K–L. Anther cap. M–N. Pollinarium. Illustration by M.F. Negrão.

FIGURE 3. Catasetum × sheyllae (male flowers). A. Habit with male and female inflorescences. B. Floral bract. C–E. Flowers. F. Perianth. G–I. Lip. J–L. Column. M–N. Anther cap. O–P. Pollinarium. Photographs by A.H. Krahl.

FIGURE 4. Catasetum × sheyllae (female flowers). A. Flower. B. Floral bract. C. Perianth parts. D–F. Column. Photographs by A.H. Krahl.

FIGURE 5. Morphological comparison between the natural hybrid and its putative parents. A–C. Catasetum × sheyllae. D–F. Catasetum boyi. G–I. Catasetum garnettianum. Photographs by A.H. Krahl.