Thismia cordata D.F.Silva & J.M.A.Braga, 2022

Silva, Diego Ferreira Da, Ríos, Román Carlos, Cruz, Vinicyus Jorge Mordaski Visini Da, Souza, Inti De & Braga, João Marcelo Alvarenga, 2022, Thismia cordata (Thismiaceae), a new fairy lantern species from the Brazilian Atlantic Forest, Phytotaxa 571 (1), pp. 76-84 : 77-81

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

Type:— BRAZIL. Paraná: Torre Amarela, Serra do Marumbi. APA do Piraquara , 25º30’44”S, 48º59’20”W, 10 January 2022, fl., R. C. Ríos 13 (holotype UPCB [barcode UPCB0048999 , dried + in spirit!]; isotype RB [in spirit!]) .

Diagnosis:— Similar to T. glaziovii , but differs by zygomorphic flowers, perianth tube gibbous and internally densely pilose, annulus surrounded by a prominent star-shaped 6-lobed ornamentation with acute apices, densely pilose, margin ciliate; outer perianth lobes cordate and glabrous ovary with stigma sharply trilobed and densely pilose.

Description:—Herbs 4.5–10 cm tall, terrestrial, mycoheterotrophic, achlorophyllous. Roots 5–7 × 2–3 mm, tuberous with fibrous roots, 1–10 × ca. 0.5 mm, white to orange. Stem 3.5–5.5 × ca. 0.2 cm, longitudinally bisulcate, erect, unbranched, glabrous, white to orange. Involucral bracts 4; bracts 3–4 × ca. 2 mm, lanceolate, apex acute, folded up giving the false rounded, concave appearance, 1-veined, margin entire, glabrous, translucent white to orange. Flowers 23–31 × 6–9 mm, solitary, zygomorphic; perianth tube 7–8 × 8.5–9 mm, gibbous, outer surface smooth, glabrous, orange, 6-veined darkened, inner surface densely pilose with trichomes ca. 1 mm long, white, continuing ca. 1 mm above the tube closure; annulus ca. 1 mm in diameter, protruding ca. 0.4 mm above the surface, surrounded by 6 brownish spots and a prominent star-shaped 6-lobbed ornamentation with acute apices, protruding ca. 0.2 mm above the surface and with ca. 5 mm in diameter, aquamarine, surrounded by a whitish-orange narrow strip with ca. 3 mm width, densely pilose with inconspicuous trichomes, margin ciliate; perianth lobes inserted all at same height in the distal portion of the perianth (3+3); outer perianth lobes 2–4 × 2–3 mm, ovate, base cordate, with lobes detached from the insertion with the tube, apex acute, curved with a rounded appearance, 1-veined, margin entire, orange, glabrous; inner perianth lobes 1-veined, margin entire, glabrous, base ca. 1 × 2 mm, orange, terminated by a filiform appendage 15–21 mm long, orange at the base, the rest to the apex slate blue to periwinkle. Interstaminal lobes ca. 1.5 × 0.2 mm, inserted at the same level as the filaments narrowly triangular, falcate, apex rounded. Stamens 6, 2.5–3 × ca. 2 mm, glabrous, pendulous; filaments ca. 1 mm long, inserted ca. 1.2 mm below the annulus, lavender; connective ca. 2.5 × 2 mm, dilated with 4 lobes, falcate, lavender, 2-lobed at the upper ca. 1 × 0.2 mm, 2-lobed at the lower ca. 1 × 0.3 mm; anthers ca. 0.7 × 0.8 mm long, widely ovate with hippocrepiform line. Ovary ca. 2.5 × 2 mm, unilocular, top-shaped, smooth, white to orange with truncate apex slate blue, glabrous, multi-ovulate placentation parietal; style ca. 0.8 mm long, glabrous, white; stigma ca. 2 × 1.5 mm, lavender, densely pilose with trichomes white, sharply trilobed, each lobe with upper surface sepia, densely papillose, margin ciliate. Fruits unknown.

Etymology:— The specific epithet refers to the heart-shaped outer perianth lobes.

Phenology:— Flowering was observed in January.

Distribution and habitat:— So far it is known only from the Serra do Marumbi, inside the APA do Piraquara, located in the municipality of Piraquara, State of Paraná, south Brazil ( Figure 4 ). This environmental protected area was created through State Decree nº 1754 of 05/06/96 and consists of an important Atlantic Forest remnant located in the catchment area of the Piraquara River basin, tributary of the Iguaçu River, in eastern end the Serra do Mar, with an approximate area of 8,881.00 ha. The predominant climate is Cfb, with an average annual temperature of 17 ºC (20.5 ºC in January and 13 ºC in July) and annual rainfall of 1,550 mm, more concentrated in the summer months, with July and August as the driest months ( Alvares et al. 2013). We carried a search close to coordinates available in the specimen deposited in UPCB herbarium, but no individuals were found posteriorly. However, it can be observed that the specimens were collected in a conserved montane forest gradient, around 1000 m a.s.l.

Conservation status: — Thismia cordata is known only from a small population in the type location within an Environmental Preservation Area, surrounded by extensive commercial eucalyptus plantations, and pastures and with ecotourism activities. Therefore, a preliminary assessment is proposed according to the IUCN Red List Categories and Criteria, ( IUCN 2012, 2019), for critically endangered base on B2 (ab(iii)) criterion.

Morphological affinities: — Thismia cordata belongs to T. subg. Ophiomeris sect. Ophiomeris , which is characterized by tuberous underground parts, longitudinally bisulcate stem, involucral bracts present, perianth lobes inserted all at same height in the distal portion of stem, outer perianth lobes often smaller and reflexed, inner perianth lobes ascending, larger and of different shape and size, often triangular with filiform appendage, stamens with ribbonshaped filaments, connective dilated, interstaminal lobes present, stigma trilobed or one capitate, and ovary with parietal placentation, inserted near the base to half way up the ovary ( Maas et al. 1986). According to Shepeleva et al. (2020), T. subg. Ophiomeris has strong phylogenetic affinity to the Neotropical monotypic genus Tiputinia P.E.Berry & C.L.Woodw. (in Woodward et al. 2007: 158), but in this study only T. panamensis ( Standley 1927: 163) Jonker (1938: 234) was sampled, being the only species from the New World. Thus, it reinforces the need for new phylogenetic studies that include higher number of Neotropical species.

Thismia cordata is similar to T. glaziovii Poulsen (1889: 549) as it have the perianth narrowing at the apex, forming a flat surface, with a central annulus surrounded by ornamentations, and stamens with connective dilated with 4 lobes, divided into 2-upper and 2-lower. However, it differs by the perianth zygomorphic, slight gibbous (vs. actinomorphic), perianth tube with glabrous outer surface, and densely pilose inner surface (vs. both surfaces glabrous), outer perianth lobes 2–4 × 2–3 mm, ovate, base cordate with lobes detached from the insertion with the tube, apex acute, but curved with a rounded appearance (vs. outer perianth lobes 0.5–2 × 2–5 mm, deltate, base fully connected to the tube, apex acute), inner perianth lobes with base very narrow, ca. 1 mm long, terminated by a filiform appendage 15–21 mm long (vs. inner perianth lobes with base deltoid, 2.5–3.5 mm long, terminated by a filiform appendage 7.5– 11 mm long), annulus ca. 1 mm in diameter, surrounded by 6 brownish spots and 6-lobed star-shaped ornamentation, protruding ca. 0.2 mm above the surface, densely pilose, ciliate (vs. annulus ca. 3 mm in diameter, surrounded by an 6-lobed ornamentation, each V-shaped lobe surrounded by an projection arch-shaped in the distal portion, protruding ca. 0.2 mm above the surface, papillose). The complete comparison of the morphological characters of these species is shown in Table 1 .

Figures

FIGURE 1. Thismia cordata. A. Flowering habit. B. Bract. C. Top view of the flower, showing the arrangement of the perianth lobes, and annulus surrounded by star-shaped ornamentation. D. Detail of the trichomes in ornamentation surrounding the annulus. E. Longitudinal section of perianth tube with trichomes inner surface, stamens, interstaminal lobes, and stigma. F. Detail of trichomes on the inner surface of the perianth tube. G. Outer perianth lobe ovate, with base cordate, and apex acute, but curved with a rounded appearance. H. Inner perianth lobe with very narrow base and evident filiform appendix. I. Stamen. J. Stigma. K. Transversal section of the ovary. L. Placentation. Drawing by Marcus Falcão.

FIGURE 2. Thismia cordata. A-B. Flowering habit. C–D. Flowers, side and front view, respectively. E. Annulus surrounded by a starshaped 6-lobed ornamentation, densely pilose and ciliate. F. Detail of the outer perianth lobes cordate. G. Longitudinal section of perianth tube densely pilose, with inner and outer lobes, stamens, interstaminal lobes, and stigma. H. Stigma. Photographs by Román Carlos Ríos.

FIGURE 3. Thismia cordata (Photos of the material in alcohol, disregard coloration). A. Flowering habit. B. Bract. C. Flower. D. Top view of the flower. E. Perianth lobes F. Inner perianth lobe. G. Outer perianth lobe. H. Longitudinal section of perianth tube with inner and outer lobes, stamens, interstaminal lobes, and stigma. I. Longitudinal section of perianth tube with inner and outer lobes, falcate stamens, interstaminal lobes, and evidencing a dense covering of trichomes around the annulus. J. Stamen. K. Longitudinal section of ovary showing the ovules, style, and stigma. Photographs by Diego Ferreira da Silva.

FIGURE 4. Distribution map and habitats of Thismia cordata. A. Distribution of T. cordata. B. Delimitation of the municipality of Piraquara, Paraná, Brazil. C–D. Panoramic views of the areas habited by T. cordata, showing the Serra do Marumbi andAPA do Piraquara, Paraná, Brazil [satellite images by ESRI obtained in 2022].