Thismia mantiqueirensis Engels & E.C.Smidt

Engels, Mathias Erich, Muscat, Edelcio, Moroti, Matheus De Toledo & Smidt, Eric De Camargo, 2022, Thismia mantiqueirensis (Thismiaceae), a new species of Brazilian Atlantic Rainforest, Phytotaxa 570 (2), pp. 223-228 : 224-227

Thismia mantiqueirensis Engels & E.C.Smidt sp nov. ( Figures 1–2 )

Type: — BRAZIL. São Paulo, São José dos Campos, Subdistrito de São Francisco Xavier, Serra da Mantiqueira , fl. and fr., 13 February 2020, E. Muscat & M.T. Moroti s/n (Holotype MBM 436.311!, Isotype UPCB! [spirit]) .

Similar to Thismia glaziovii Pouslen , but it differs by floral tube without fovea at the base, the tepals with pilose lamellae irregularly distributed at the adaxial surface; obovate shortest tepals, comparatively larger; and by the anthers with an entire and rounded apex.

Description:— Herb 4.3–12 cm tall. Roots 1–3.5 cm long, filiform, white. Tuber 6–8 × 4 mm, cylindric, brown. Stem 3.7–11.6 × 0,1–0,15 cm, sub-cylindric, longitudinally bisulcate, white to white-brownish. Leaves 3–4, 2.5–4 × 1.5–2.5 mm, scale-like, verticillated right below the flowers, cucullate, oblanceolate to obovate, acute base, entire margins, apse obtuse to rounded, white. Flower 14–25 × 9–11 mm, actinomorphy, campanulate, sessile; ovary 2–3 × 3 mm, conical, white with blue base and brown-orange stripes; placentation parietal, inserted near the base to half way up the ovary; flower tube 7–8 × 10–11 mm, conical, smoothly pilose, orange with blue base; upper disc of the floral tube adorned with six V-shaped calluses, blue with orange calluses; tepals in two distinct morphologies (3+3), inserted all at the same height in the distal portion of the flower tube, smoothly pilose in both surfaces; adaxial surface with irregularly distributed lamellae; lamellae 0.5–0.7 mm, laminate, pilose; shortest tepals ca. 4 × 3.5 mm, laminar, obovate, base acute, entire margin, apex rounded-obtuse, orange; longest tepals 7–8 × 2.5 mm, large-ovate, base truncate, entire margin, apex long apiculate, orange; apiculate of inner tepals 10–18 mm comp., filiform, acute, paleorange; and annulus ca. 1 mm diam. in the centre of the upper disc of the floral tube, rounded, margins thickened, orange. Anther ca. 2,5 × 1 mm, apex rounded, flattened, pair of auricles at the base of thecae; auricles ca. 1.5 mm long, oblong-filiform, incurved in natural position; filament ca. 1 mm length, oblong. Stigma 2,5–3 × 2–2,5 mm, capitate, ovate to rounded, trilobed, pale orange. Fruit ca. 4 × 5 mm, cup-shaped, margins thickened, stripes smoothly carinate, white with margins and stripes pale brown-orange; not etiolated.

Distribution and ecology: —Known only in the type locality, Toca do Muriqui, in the São Francisco Xavier sub-district, São José dos Campos municipality, São Paulo state. São Francisco Xavier is located in the Mantiqueira mountains, characterised by typical Atlantic Forest formations (750 to 2,000 m a.s.l.), with patches of rocky outcrops and many rocky streams. The region has seasonal climate variations, with the dry season occurring from April to August (average temperature in July is 15.5˚C) and the wet season between September and March (average temperature in January is 21.6˚C) (climate-data.org 2022). It is possible the species only occurs in cloud and altitude montane forests, at about 1,200 m above sea level. During the rainy season, it was possible to see some flowering individuals in the leaf litter near tree roots.

Etymology: —The specific epithet refers to the Mantiqueira mountains, where the species was discovered.

Conservation status: —According to the IUCN criteria (2017), Thismia mantiqueirensis could be assessed as Data Deficient (DD). Known only from one collection, it needs more sampling focus, which may result in the finding of more populations in different localities, increasing knowledge of the actual conservation status of this new species. The trail where the plant was found is frequently used for ecotourism, which can lead to problems for the conservation of the species.

Taxonomic discussion: — Thismia mantiqueirensis belongs to Thismia Griffith (1845: 221) subgen. Ophiomeris ( Miers 1847: 328) Maas et al. (1986: 145) sect. Ophiomeris due to the presence of a tuberous stem with several filiform roots; a longitudinally bisulcate stem with leaves condensed in the distal portion and juxtaposed to the flower; shortest and longest tepals distinct from each other but arranged at only one whorl at the top of the floral tube; trilobed capitate stigma; anther with filiform filaments; and by parietal placentation. Despite the classification in the section Ophiomeris , the new species has the stamens with an entire and rounded apex (not 2-lobed), and the absence of interstaminal lobes, as described in this section.

Thismia mantiqueirensis is similar to T. glaziovii Pouslen (1889: 549) due to its campanulate flowers and an infundibuliform tube with an ornamented disc. It can be distinguished by the absence of internal fovea at the base of the floral tube (vs. with fovea); internal and external tepals with hairy lamellae irregularly oriented on the adaxial surface (vs. six continuous thickened lamella forming a disc or a long segmented disc); shorter obovoid tepals, developed, ca. 4 mm long (vs. deltoid, poorly developed, ca. 0.5–2 mm long); inter-staminal lobes absent (vs. absent or present) and by the anthers with entire and rounded apex (vs. bilobed apex with acute lobes).

Thismia itatiaiensis Brade (1943: 47) was described from fruiting material collected in Itatiaia, state of Rio de Janeiro, Brazil. Later, Brade (1946: 41) amended this name with a flowering specimen from the same place, comparing and differentiating it from T. glaziovii for presenting the upper disc of the floral tube as almost smooth and not crested (i.e. smooth-ribbed), by the scaled appendages of the perianth, presence of inter-staminal lobes and by the capitate stigma. These distinctive features were considered and included as variations of T. glaziovii by Maas et al. (1986).

Thismia mantiquirense differs from the Itatiaia’s material by floral tube without fovea at the base (vs. with fovea); the tepals with pilose lamellae irregularly distributed at the adaxial surface (vs. six continuous thickened lamella forming a disc or along segmented disc); an upper disc of the floral tube adorned with six V-shaped calluses (vs. with smooth-ribbed); obovate shortest tepals, comparatively larger (vs. deltoid, poorly developed, ca. 1 mm long); interstaminal lobes absent (vs. present) and by the anthers with an entire and rounded apex (vs. bilobed apex with acute lobes).

Thismia hyalina ( Miers 1866: 474) Bentham & Hooker ex Mueller (1891: 234) was the only species known for the state of São Paulo (Maas-van de Kamer & Maas 2016, Flora e Funga do Brasil 2022). Thismia mantiqueirensis can be distinguished from T. hyalina by the expressive presence of filiform roots in the tuberous stem (vs. tubers with few roots); campanulate flowers (vs. erect flowers); tepals inserted at the same height of the floral tube, both laminar (vs. inserted in two distinct series, the external tepals cylindrical and filiform); stigma capitate (vs. elliptical with acute and ascending lobes); and by non-etiolated fruit (vs. etiolated).

Figures

FIGURE 1. Thismia mantiqueirensis Engels & E.C.Smidt sp. nov. A. Habit. B. Detail of stem in transversal section. C. Leaf. D. Flower in sagittal section. E. Detail of stigma. F. Frontal view of distended tepals and upper disc of the floral tube. G. Detail of tepal lamellae. H. Detail of trichomes from abaxial surface of tepals. I. Detail of trichomes of the adaxial surface of tepals. J.Anther in frontal view. K.Anther in lateral view. L. Mature fruit and leaves in lateral view. M. Mature fruit in dorsal view. Drawn by M.E. Engels based on the type.

FIGURE 2. Thismia mantiqueirensis Engels & E.C.Smidt sp. nov. A. Habit in litter, individuals in blooming and in bud. B. Detail of flower in lateral view. C. Detail of flower in diagonal view, evidencing the upper disc of the floral tube and perianth lamellae. D. Habit in litter of flowering and fruiting individual. Photos: B by M.T. Moroti and A, C, D and E by E. Muscat, all photos from the type material.