Clematis serrana Piovesani, P.P.A.Ferreira & G.Seger

Piovesani, Willian Souza, Ferreira, Priscila Porto Alegre & Seger, Guilherme Dubal Dos Santos, 2024, Clematis serrana (Ranunculaceae), a new endemic species to the Atlantic Forest highlands in Southern Brazil, Phytotaxa 660 (2), pp. 149-160 : 150-156

Clematis serrana Piovesani, P.P.A.Ferreira & G.Seger , sp. nov.

TYPE:— BRAZIL. Santa Catarina: Urubici. Parque Nacional de São Joaquim , Trilha da Pedra Furada , transição da floresta com araucária altomontana com o campo, 28º07’29.9”S 49º28’24.7”W, 1,756 m elev., 30 January 2023 (staminate fl.), W. S. Piovesani, G. D. S. Seger & F. P. Silveira 250 (Holotype: ICN, isotypes [in process of distribution]: FLOR, RB) .

Diagnosis: — Clematis serrana shares vegetative similarities with both C. denticulata and C. ulbrichiana , characterized by toothed leaflet blades and bipinnate leaves (tripinnate in C. ulbrichiana ). However, it distinguishes itself from both of these species particularly in terms of reproductive characteristics, as the staminate partial inflorescence in compressed cymes (vs. normal cymes), pyriform staminate flower buds (vs. obconic), and 20–30 carpels (vs. 30–75).

Description:—Woody climbers, up to 10 m high, with twining leaves (rachis or petiolules), dioecious. Stems cylindrical, striate, ridged, and shreddy when old, glabrous or sparsely sericeous, indumentum denser at the nodes. Leaves imparipinnate or bipinnate, 2–3 pairs of pinnae, pinnae 1–3-foliolate. Petioles canaliculate, 38–55 × 1–1.6 mm, glabrous or sparsely sericeous, indumentum denser at the apex. Foliar rachis cylindrical, 60–110 × 1–2.2 mm, glabrous or sparsely sericeous, indumentum denser at the nodes. Petiolules narrowly canaliculate, primary 6–33 × 0.4–1 mm, sericeous at the apex, secondary 1.5–20 × 0.3–0.5 mm, sericeous. Leaflet blades ovate, 19–60 × 12–30 mm, chartaceous or membranous, apex angle acute, apex shape straight, apiculate, base angle obtuse, base shape rounded or concave-convex, margin toothed, with 1–6 pairs of teeth, incised 1/3 to 1/2 of the distance to the midvein, glabrous or sparsely sericeous, actinodromous, 3 or 5 primary veins, prominent on the abaxial surface, impressed on the adaxial, secondary veins conspicuous on both surfaces. Inflorescences thyrsoids or dithyrsoids, axillar or terminal, 2–3 levels of branching, sometimes reduced to a single axis and a false whorl of flowers at the apex, 6–18 flowers, primary branch 38–210 × 1.2–2 mm, up to 5 nodes, glabrous or sparsely sericeous, secondary branch 17–60 × 0.6–1.2 mm, up to 2 nodes, tomentose, tertiary branch 8–10 × 0.4 mm, single node, tomentose, primary bracts oblanceolate, trilobate, 3 or 5-foliolate, 8–20 × 1.2–3.5 mm, sparsely sericeous, secondary bracts linear or oblanceolate, 4–9 × 1 mm, sericeous, bracteoles linear or oblanceolate, 2.5–5 × 0.6–0.8 mm, sericeous. Staminate flowers partial inflorescences in compressed cymes (false whorls), originated by reduction of the main axis, pedicels 9–16 × 0.4–0.5 mm, tomentose, buds pyriform, 5–7.5 × 3.5–5 mm, sepals 4 or 5, elliptic or obovate, 6–7.5 × 3–4.5 mm, adaxial surface tomentose, abaxial sericeous, margin hoary, stamens 19–30, filaments 4.5–6.2 mm long, glabrous, anthers 1–1.3 mm long, pistillodia glabrous, 1–1.2 mm long. Pistillate flowers partial inflorescences in dichasial cymes, pedicels 8–19.5 × 0.3–0.8 mm, tomentose, buds elliptic, 3.2–6 × 2.8–5 mm, sepals 4(–5), obovate, 6–7.5 × 3–3.5 mm, adaxial surface tomentose, abaxial sericeous, margin hoary, carpels 20–30, 5–7 mm long in anthesis and up to 50 mm in fruit maturity, staminodes caducous, glabrous, 3–3.5 mm long. Achenes ovate, elliptic or obovate, 1.4–2.2 × 1–1.5 mm, pubescent. Figures 1 and 2 .

Paratypes: — BRAZIL. Santa Catarina: Bom Jardim da Serra, Serra do Oratório , 1,400 m elev., 12 January 1969 [stam. fl.], Reitz & Klein 8124 (FURB!, HBR!, ICN!, L image!, P image!, U image!, US image!) ; Bom Retiro, campo between Fazenda Santo Antônio and Fazenda Campo dos Padres , 1,400 –1,650 m elev., 24 January 1957 [stam. fl.], L.B. Smith & R. Reitz 10413 (HBR!, R!, US image!) ; [ Bom Retiro ], Campo dos Padres, 23 January 1957 [stam. fl.], B. Rambo 60146 (PACA!) ; Bom Retiro, Granja Invernadinha , 15 February 1954 [sterile], J. Mattos s.n. (HAS 95748!) ; Lauro Müller, Serra do Oratório, Trilha do Cabo Aéreo , interior de floresta atlântica altomontana, 28º22’20.5”S 49º33’27.5”W, 1,351 m elev., 15 January 2020 [stam. fl.], W. S. Piovesani, P. P. A. Ferreira & J. F. Soares 189 (ICN!) ; Lauro Müller, Serra do Oratório, Trilha do Cabo Aéreo , interior de floresta atlântica altomontana, 28º22’19.7”S 49º33’27.6”W, 1,370 m elev., 28 January 2023 [pist. fl., fr.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 235 (ICN!) ; Lauro Müller, Serra do Oratório, Trilha do Cabo Aéreo , interior de floresta atlântica altomontana, 28º22’20.0”S 49º33’27.5”W, 1,356 m elev., 28 January 2023 [stam. fl. with vestigial pist. fl.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 236 (ICN!) ; Lauro Müller, Serra do Oratório, Trilha do Cabo Aéreo , interior de floresta atlântica altomontana, 28º22’20.1”S 49º33’27.3”W, 1,350 m. elev., 28 January 2023 [stam. fl.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 237 (ICN!) ; Orleans, Parque Nacional de São Joaquim, Trilha da Pedra Furada , interior de floresta atlântica altomontana, 28º08’01.6”S 49º28’36.6”W, 1,613 m elev., 30 January 2023 [stam. fl.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 252 (ICN!) ; São Joaquim, near Mantiqueira (27 km east of São Joaquim ), 1,100–1200 m elev., 16 January 1957 [stam. fl.], L.B. Smith & R. Reitz 10220 (HBR!, P image!, R!, US image!) ; Urubici, Morro da Igreja , 03 January 1949 [stam. fl.], R. Reitz 2958 (HBR!, US image!), R. Reitz 4994 (PACA!) ; Urubici, Parque Nacional de São Joaquim , 28°09’39.0”S 49°38’11.0”W, 26 February 2015 [fr.], A. Nuernberg et al. 1743 (FLOR!) ; Urubici, Parque Nacional de São Joaquim, Estrada Geral do Morro da Igreja , borda de floresta atlântica altomontana, 28º05’27.3”S 49º30’30.2”W, 1,580 m elev., 30 January 2023 [fr.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 254 (ICN!) ; Urubici, Parque Nacional de São Joaquim, Santa Bárbara , borda de floresta com araucária altomontana, 28º09’30.0”S 49º38’13.2”W, 1,624 m elev., 29 January 2023 [fr.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 243 (ICN!) ; Urubici, Parque Nacional de São Joaquim, Trilha das Nascentes do Rio Pelotas , na borda de mata ciliar do rio Pelotas , 28º08’17.7”S 49º29’59.8”W, 1,527 m elev., 05 January 2023 [pist. fl.], G. D. S. Seger & E. Bach 930 (ICN!) ; Urubici, Parque Nacional de São Joaquim, Trilha das Nascentes do Rio Pelotas , borda de mata ciliar, 28º08’17.7”S 49º29’59.8”W, 1,527 m elev., 31 January 2023 [fr.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 258 (ICN!) ; Urubici, Parque Nacional de São Joaquim, Trilha das Nascentes do Rio Pelotas , borda de mata ciliar, 28º08’17.7”S 49º29’59.8”W, 1,527 m elev., 31 January 2023 [stam. fl.], W. S. Piovesani, G. D. S. Seger & F. P. Silveira 259 (ICN!) ; Urubici, Vacas Gordas , 05 February 1963 [fr.], R. Reitz 6682 (FURB image!, HBR!, P image!) ; Urupema , 1,200 m elev., 24 December 1962 [pist. fl.], Reitz & Klein 14561 (FURB image!, HBR!, P image!) .

Distribution and habitat: —The species is exclusively found within the Brazilian Atlantic Forest Biome (IBGE 2019), Atlantic and Araucaria Forest biogeographic provinces ( Morrone et al. 2022), in the South Brazilian Plateau formation, Santa Catarina state. Its recorded elevational range spans from 1,100 to 1,756 m above sea level ( Figure 3 ). This species predominantly occupies the fringes of upper montane and riparian forests, often associated with highland shrubby grasslands.

Phenology: —Individuals bearing staminate flowers were collected only in January, whereas those with pistillate flowers were observed in December and January. Individuals with fruits were collected in January and February.

Etymology: —The specific epithet derives from the name of the geological formation where the species is found, “Serra Geral”, meaning “that lives in Serra”.

Preliminary extinction threat assessment: —We assessed Clematis serrana as Endangered (EN) according to IUCN (2022) categories and criteria B1b(I,ii,iii)c(i,ii). Its Area of Occupancy (AOO) is 44 km ² and its Extent of Occurrence (EOO) is 1,970 km ². The primary threat to the species is habitat fragmentation, resulting from soil conversion for annual crops such as corn and soy, which has led to a continuous decline and extreme fluctuations in the extent of occurrence and area of occupancy. Another contributing factor to its ongoing decline is climate change, as the species is adapted to the cold temperatures of the Southern Brazilian Plateau, where the mean annual minimum temperatures hover around 8 to 10º C ( Pandolfo et al. 2002). The species is known from very few locations, with most of them situated near or within the São Joaquim National Park protected area ( Figure 3 ), which is a favorable aspect for its conservation.

Notes on the history of collections and taxonomy: —The species was first collected by Raulino Reitz in 1949, in Morro da Igreja, Urubici, Santa Catarina (Reitz 2958). At that time, it was identified as Clematis hilarii Sprengel (1828: 177) , a species widely distributed in West South America, encompassing the Esteros del Iberá, Pampean, Chaco, Yungas, and Desert biogeographic provinces ( Morrone et al. 2022), extending from Argentina to southern Peru. In 1956, Alicia Lourteig reinstated the name C. denticulata ( Lourteig 1956) and considered C. hilarii as a synonym. Alicia identified the populations on the South Brazilian Plateau as C. denticulata var. ulbrichiana ( Lourteig 1966) , the same taxon initially described to Itatiaia, Rio de Janeiro, based on leaf characteristics. More recently, Moreno (1993, unpublished thesis) synonymized C. denticulata into C. campestris A.St-Hil. (1825: 4) and elevated C. ulbrichiana to the species level. Johnson (1997, 2001) and Grey-Wilson (2000) followed Lourteig (1956) and kept C. campestris and C. denticulata as distinct taxa, and C. ulbrichiana as a variety of the latter. Wang (2004) adopted Moreno’s circumscription and treated C. campestris as a very plastic species, encompassing several synonyms.

The synonymization of C. denticulata resulted in a significant amount of morphological variability in C. campestris . Therefore, based on our research, we consider all these taxa to be distinct species. Clematis denticulata differs from C. campestris by the unisexual flowers (vs. perfect flowers) ( Figure 4 ) and C. ulbrichiana is distinct from all other Clematis taxa in Brazil by the mature tripinnate leaves ( Figure 5 ). Clematis denticulata is sympatric with C. serrana , but has a much wider distribution range, while C. ulbrichiana is restricted to the Itatiaia National Park, in Rio de Janeiro ( Figure 6 ). Wang (2004) identified five specimens as C. ulbrichiana that we attribute to the new species: Reitz 6682 (P image!), Reitz & Klein 8124 ( US image!), Reitz & Klein 14561 (P image!), L.B. Smith & Reitz 10220 (P image!), and L.B. Smith & Reitz 10413 ( US image!), all occurring in south Santa Catarina. In the same area, the author identified two specimens as C. campestris that we recognize as C. denticulata : Reitz 2722 ( US image!) and Klein 4515 (P image!). Most taxonomic studies of South American species of the genus have primarily relied on vegetative characters rather than reproductive ones ( Lourteig 1951, 1956, 1963, 1966, Molero 1985, Bacigalupo 1987). Nevertheless, we have observed that a combination of both reproductive and vegetative characteristics is essential for accurately delimiting the species.

Figures

FIGURE 1. Vegetative characteristics of Clematis serrana A. Ridged bark with ca. 4.5 cm DBH. B. Shreddy bark with persistent twining petioles. C. Stem cross-section with secondary growth. D. Habit. E. Inflorescence branch, showing the primary 5-foliolate bracts with almost entire leaflets. F. Mature bipinnate leaf with toothed leaflets. Scale bar: 10 mm.

FIGURE 2. Reproductive characteristics of Clematis serrana (Ranunculaceae). A. Staminate inflorescences, showing the partial inflorescences in compressed cymes (false whorls). B. Staminate flowers with pistillodes (red arrow). C. Pistillate inflorescence, showing the partial inflorescences in dichasial cymes. D. Pistillate flower on anthesis with staminodes (red arrow). E. Infructescence. F. Achenes with the long accrescent styles. Scale bar: 5 mm.

FIGURE 3. Distribution map of Clematis serrana (Ranunculaceae), indicating the species known localities in the South Brazilian Plateau, Santa Catarina state, Brazil.

FIGURE 4. Vegetative and reproductive characteristics of Clematis denticulata (Ranunculaceae). A. Apical 5-foliolate leaf with toothed and lobed leaflets. B. Mature bipinnate leaf with entire leaflets. C. Staminate partial inflorescence (normal cyme). D. Pistillate partial inflorescences; staminodes (red arrow). E. Infructescence. Scale bar: 5 mm. Photo D: Sérgio Bordignon.

FIGURE 5. Paratype of Clematis ulbrichiana and holotype of C. serrana(Ranunculaceae).A. Campos Porto2710 (RB). B. W.S.Piovesani, G.D.S. Seger & F.P. Silveira 250 (ICN).

FIGURE 6. Distribution map of Clematis denticulata, C. serrana, and C. ulbrichiana (Ranunculaceae). Country codes are indicated in black letters and Brazilian state codes are indicated in gray letters.