Thismia calcarata D.F.Silva, Honório & J.M.A.Braga, 2023

Silva, Diego Ferreira Da, Honório, Mayk, Silva, Chirley Gonçalves, Teixeira-Silva, Márcia A., Silveira, Marcos & Braga, João Marcelo Alvarenga, 2023, Two new species of Thismia (Thismiaceae) from the Brazilian Amazon Forest, Phytotaxa 587 (3), pp. 269-282 : 270-274

Thismia calcarata D.F.Silva, Honório & J.M.A.Braga , sp. nov. ( Figures 1–3 )

Type:— BRAZIL. Acre: Manoel Urbano, Parque Estadual Chandless , Bacia do Rio Purus , Rio Chandless , Floresta Ombrófila Aberta com bambu e palmeiras, 09°23’25”S 69°55’11”W, 14 April 2021, fl. and fr., M. H. Oliveira et al. 233 (holotype: UFACPZ [dried + in spirit]) .

Diagnosis:— Thismia calcarata is similar to Thismia panamensis , but it can be easily recognized by the presence gibbous part of the floral tube with one longitudinal slit; slit’s opening resembling to a spur; annulus ca. 2 mm in diam., magenta, ornamented by two rings; outer tepals ca. 4 × 3 mm, obovate, concave, reflexed, glabrous, margin lacerate, slightly dentate to ciliate, apex rounded to obtuse; interstaminal lobes absent; stamens ca. 2 × 1.5 mm; connective dilated 4-lobed, translucent white, 2-lobed at the upper ca. 0.8 × 0.4 mm, triangular to deltoid, 2-lobed at the lower ca. 0.1 × 0.1 mm, inconspicuous lobes, auriculate and stigma trilobed, lobes ascendants with apex slightly curved to the center, densely pilose.

Description:—Herbs 8.3–8.6 cm tall, terrestrial, mycoheterotrophic, achlorophyllous. Roots 7–12 × 5–6 mm, tuberous with fibrous roots, 1–10 × ca. 1 mm, white to orange. Stem 5.2–7.5 × ca. 0.2 cm, longitudinally bisulcate, erect, unbranched, glabrous, white. Involucral bracts 4; bracts 3–5 × 1–2 mm, lanceolate, concave appearance, 1- veined, margin entire or sparsely serrate, apex obtuse, glabrous, white. Flowers 31–35 × ca. 8 mm, solitary, slightly zygomorphic; floral tube 7–9 × ca. 8 mm, gibbous part of the floral tube with one longitudinal slit, slit’s opening resembling to a spur, outer surface smooth, glabrous, white, with 12-veined darkened, inner surface densely pilose with trichomes ca. 0.4 mm long, concentrated from the base to the middle portion of the tube, white; annulus ca. 2 mm in diam. magenta, outermost ring 3-lobed, each lobe alternating with the tepals, erect apical margin, 3–3.2 × 1.7–2 mm, colliculate on both surfaces, innermost ring 6-lobed, ca. 1.5 × 0.1 mm, hexagonal, magenta. Tepals inserted all at same height in the distal portion of the floral tube (3+3[4]); outer tepals ca. 4 × 3 mm, reflexed, obovate, concave, base truncate, 1-veined, margin lacerate, slightly dentate to ciliate, apex rounded to obtuse, whitish; inner tepals erect with base very narrow, base ca. 2 × 1.2 mm, terminated by a flagelliform appendage 22–26 mm long, 1-veined, margin entire, apex plane, glabrous, coppery at the 2/3, the rest to the apex white. Interstaminal lobes absent. Stamens 6, ca. 2 × 1.5 mm, pendulous; filaments ca. 1 mm long, inserted just below the annulus, translucent white; connective ca. 1 × 1.5 mm, dilated, 4-lobed, translucent white, 2-lobed at the upper ca. 0.8 × 0.4 mm, triangular to deltoid, 2-lobed at the lower ca. 0.1 × 0.1 mm, inconspicuous lobes, auriculate; anthers ca. 0.5 × 1 mm, inserted in the medial portion of the dilated connective, widely ovate, yellow with hippocrepiform line. Ovary ca. 2 × 3 mm, unilocular, top-shaped, smooth, white, glabrous, multi-ovulate, placentation parietal; style ca. 1 mm long, glabrous, white; stigma ca. 1.6 × 1 mm, trilobed, inconspicuous lobes, ascendants with apex slightly curved to the center, densely pilose, trichomes ca. 0.3 mm. Fruits 4–8 × 5–8 mm, cup-shaped, inner surface glabrous, margin irregular, ciliate, with 6 symmetrical lobes 2–3 × ca. 0.1 mm, rounded, emarginate, glabrous, white. Seeds 0.3–0.4 × ca. 0.2 mm, ovoid to elipsoid, reticulate, tancolored, seminiferous nucleus brown, funiculus filiform, persistent, translucent white.

Etymology:— The specific epithet refers the gibbous part of the flower resembling to a spur.

Phenology:— Flowering and fruiting observed in March to April.

Additional specimens examined (Paratypes): — BRAZIL. Acre: Manoel Urbano, Parque Estadual Chandless, Bacia do Rio Purus , Rio Chandless , Floresta Ombrófila Aberta com bambu e palmeiras, 09°22’24.5”S, 69°55’22.3”W, 28 March 2021, fr., M. H. Oliveira et al. 232 ( UFACPZ [dried + in spirit]); Ibidem , 09°23’51.2”S, 69°54’58.8”W, 16 March 2021, fr. M. H. Oliveira et al. 236 ( UFACPZ [dried + in spirit]) .

Distribution and habitat:— Thismia calcarata is known only from three localities, collected in permanent plots the Program for Biodiversity Research (PPBio), implemented in the Parque Estadual Chandless (PE Chandless) (see Figure 7 A-B). The individuals were found growing amongst leaf litter, under shade in Open Ombrophilous Forest with a predominance of bamboo and palm trees. Created by Decree 10.670 of 02/09/2004, the PE Chandless is the second largest protected area of the State of Acre with 695.3 thousand ha., bordered in Brazil by the Alto Purus and Mamoadate Indigenous Lands and by the Cazumbá-Iracema Extractive Reserve ( SEMAPI 2022). On the international border with Peru, the PE Chandless is bordered by the State Reserve for Isolated Indigenous Peoples of Madre de Dios and the Murunahua Territorial Reserve in the Ucayali Region ( SEMAPI 2022).According to the K̂ppen classification, the predominant climate is Af, with an average annual temperature between 22º to 24 ºC and annual rainfall between 1900– 2.200 mm ( Alvares et al. 2013).

Conservation status: — Thismia calcarata is known only from three localities collected in the PE Chandless. The PE Chandless consist an important conservation unit for the southwestern portion of the Amazon, and together with the other units it has been acting as a barrier against the advance of deforestation and fires, which permeate the loss of native forest cover and its transformation into agricultural activities ( Fearnside 2005; Silva et al. 2021). According to Silva et al. (2021), among the threats to the conservation units in Acre are the weakening of public policies, directly impacting the environmental protection agencies and making it impossible to effectively monitor practices such as deforestation, biopiracy, and hunting, among others.

Although the PE Chandless does not present imminent activities that could compromise the populations of T. calcarata , only 6 individuals are known and with restricted distribution less than 5 localities. From these set of records, it was possible to estimated the EOO at 1, 13 km 2 and AOO estimated at 12 Km 2. Therefore is assigned a preliminary conservations status for Vulnerable (VU) by meeting the criteria D1+2, according to the IUCN Red List categories and criteria ( IUCN 2012, 2022).

Morphological affinities: —According to the classification of Mass et al. (1986), Thismia calcarata belongs to T. subg. Ophiomeris sect. Ophiomeris . This group comprises species with great morphological variation in the symmetry and indumentum of the floral tube, shape of the tepals and ornamentation of the annulus.

Thismia calcarata is morphologically similar to T. panamensis ( Standley 1927: 163) Jonker (1938: 234) when compared to the external morphology, but differs by to floral tube with the gibbous part resembling a spur (vs. spur absent), outer tepals reflexed to patent, obovate, concave, margin lacerate, slightly dentate to ciliate (vs. outer tepals reflexed, ovate to broadly ovate, plane to little concave, margin entire), inner tepals erect with base narrowly triangular (vs. inner tepals reflexed with base ovate), annulus hexagonal, surrounded by two rings, colliculate on both surfaces (vs. annulus hexagonal to circular, surrounded by three rings, inner surface pilose), connective dilated, 2-lobed at the upper ca. 0.8 long, triangular to deltoid and 2-lobed at the lower ca. 0.1 mm long, inconspicuous lobes, auriculate (vs. conective dilated, 2-lobed at the upper ca. 0.7 mm long, triangular and 2-lobed at the lower ca. 0.5 mm long, conspicuous lobes, filiform), interstaminal lobes absent (vs. interstaminal lobes present) and stigma with lobes inconspicuos (vs. stigma with lobes conspicuos). For a detailed comparison of morphological characters among T. calcarata and related species (see Table 1 .)

Figures

FIGURE 1. Thismia calcarata. A-B. Panoramic views of the areas habited by T. calcarata. C-D. Flowering habit (in situ). E-F. Fruiting habit (in situ). Photographs by by Mayk Honório Oliveira.

FIGURE 2. Thismia calcarata. A–B. Flowering and fruiting habit. C. Detail of the gibbous part of the flower resembling to a spur. D. Top view of the flower, showing the arrangement of the tepals, and annulus surrounded by three rings. E. Detail of de flower, upper view. F. Fruiting habit. G. Fruit, upper view. Photographs by Mayk Honório Oliveira.

FIGURE 3. Thismia calcarata. A. Flowering habitat. B. Bract. C. Flower. D. Detail of the surface of the annulus ornamentation. E. Detail of the gibbous part of the flower resembling to a spur, showing slit. F. Longitudinal section of floral tube with inner and outer tepals, stamens, and trichomes on the inner surface. G. Stamen. H. Longitudinal section of ovary showing the ovules, style, and stigma. I. Young fruit with seeds. J. Mature fruit without seeds. K. Seeds. Photos A-I are provenient of the material in alcohol, disregard coloration. Photographs by Diego Ferreira da Silva.

FIGURE 7. Distribution map. A. Distribution of T. calcarata and T. variabilis. B. Delimitation of the Parque Estadual Chandless, Manoel Urbano, Acre, Brazil. C. Delimitation of the Reserva Florestal Humaitá, Porto Acre, Acre, Brazil (satellite images by Google sattelite obtained in 2022).