Waltillia itambana T. Machado & Versieux, 2021

Machado, Talita M., Pivari, Marco Otávio D. & Versieux, Leonardo M., 2021, Expanding Waltillia: an addition to a previously monotypic genus of Bromeliaceae from the Espinhaço range, Brazil, Phytotaxa 491 (1), pp. 1-11 : 2-9

Waltillia itambana T. Machado & Versieux , sp. nov.

Waltillia itambana is distinguished from W. hatschbachii by forming a water-impounding rosette (vs. non-impounding rosette), shorter leaf blade (up to 30 cm long vs. longer than 55 cm), leaf blade not canaliculate (vs. strongly canaliculate); longer inflorescence peduncle (ca. 174 cm long vs. 75–110 cm long), upper peduncle bracts ovate with obtuse apex (vs. narrowly lanceolate to ovate with Long-attenuate-acute apex), floral bracts completely covering the sepals (vs.

equalling 3/5 to 5/6 of the length of the sepals), flowers suberect to divergent at anthesis, not secund (vs. distinctly downwardly secund at anthesis), and the internodes of the rachis shorter (1–1.2 cm long vs. 1–3.5 cm long).

Type:— BRAZIL. Minas Gerais: Santo Antônio do Itambé, Parque Estadual Pico do Itambé , 1588 m elev., 12 June 2018, J. A. M . Souza 295, J. A. M. Paiva & S. H. A . Silva ( BHCB 192312 ) .

FIGURE. Waltillia itambana . A. Flowering individual in the rupestrian grassland habitat of Parque Estadual do Pico do Itambé. B. Water impounding leaf rosette. C. Detail of the simple inflorescence. D. suberect distichously arranged flowers. E. Flower detail showing the anther with introrse dehiscence and convolute-blade II stigma type. Photographs by Júlia A. M. Paiva.

Plants terrestrial or saxicolous, flowering ca. 2.20 m high with an extended inflorescence. Leaves 20 to 30 in number, spirally arranged, suberect, forming a water-impounding infundibuliform rosette; sheaths elliptic, ca. 12.5 cm long, ca. 5.5 cm wide, densely lepidote on both sides of appressed trichomes, green; blades lanceolate, 30–37 × 2–2.5 cm, coriaceous, green on both sides, densely white lepidote adaxially with strongly appressed trichomes forming a layer, densely brown lepidote abaxially, apex acuminate. Peduncle ca. 174 cm long, ca. 1 cm in diameter, erect, brown, covered with a white wax that is lost when dry; peduncle bracts the basal ones foliaceous and many times exceeding the internodes, erect or nearly so, green, the upper ones ovate, obtuse, 5–5.5 × 4 cm, brownish, erect, equalling or slightly shorter than the internodes, its basal portion completely enfolding the peduncle, lepidote and covered by a white waxy substance (lost when dry), brown lepidote abaxially. Inflorescence (fertile part) simple, ca. 40 cm long, erect, ca. 27- flowered, rachis straight, internodes 1–1.2 × 0.8 cm. Floral bracts decurrent on the rachis, broadly elliptic, ca. 40 × 37 mm, apex rounded, brownish, lepidote on both surfaces and covered by a white waxy substance (lost when dry), convex, ecarinate to slightly carinate toward the apex, nerved when dry, completely covering the sepals, divergent with the flowers. Flowers suberect at anthesis, contiguous with each other, densely arranged and not secund at anthesis, 7–8 cm long (including the stamens), diurnal; receptacle ca. 8 mm long, glabrous; sepals elliptic, apex obtuse, ca. 32 × 14 mm, densely lepidote on both surfaces, free, slightly carinate in the proximal part, brown with light-brown margins, coriaceous; petals narrowly spathulate, apex narrowly obtuse to emarginate with the margins slightly incurved, ca. 63 × 13 mm, 4–5 mm connate at the base, light-green, blades spreading at anthesis with the tips slightly recurved, exposing the stamens, unappendaged. Stamens much shorter than the petals, nearly equalling the corolla; filament ca. 42 mm long, the antepetalous ones adnate to the petals for ca. 6 mm, the antesepalous ones adnate to the petals for 1–2 mm, slightly complanate, yellowish-green; anther linear, ca. 16 mm long, base bilobed, apex narrow obtuse, dorsifixed ca. 4 mm above the base, curved outward, introrse dehiscent; pollen oblate in shape, elliptic in outline, ca. 50 µm in diameter, exine reticulate, lumina ca. 2 µm wide with sparse granula, becoming smaller towards the sulcus, sulcate, the sulcus with margins moderate to weakly defined, covered by a kind of operculum formed by a thick exine layer that is not continuous; style equalling the corolla and stamens, light-green; ovary ca. 11 mm long, ca. 7 mm of it inferior; stigma of the convolute-blade II type, blades spreading-contorted, densely papillose, light-green, ca. 1.7 mm long. Fruits not seen.

Etymology:— The epithet “ itambana ” is a reference to the type locality, the Pico do Itambé region.

Phenology:— Flowering specimen were collected in June.

Distribution and ecology:— Waltillia itambana is restricted to Pico do Itambé State Park, in the state of Minas Gerais, Brazil. This state park encompasses one of the highest elevation areas in the Espinhaço mountain range and is situated at 61 km away from the type locality of W. hatschbachii , in the county of Gouveia, Diamantina plateau (Fig. 2). With this addition, the bromeliad flora of this State Park reaches now 12 genera and 17 species (Versieux 2008). The species described here is known from a single population with less than ten individuals observed, some occurring spatially aggregated, and exhibiting vegetative propagation with at least one axillary bud per rosette. W. itambana grows as a terrestrial on the thin layer of soil accumulated over the quartizite rock of the rupestrian grassland habitat. These plants occur at ca. 1590 m elevation, completely exposed to sunlight and close to small water streams.

Conservation status:— Although Waltillia itambana occurs within the Parque Estadual do Pico do Itambé, the proximity of the population to the edges of the conservation unit does not guarantee the quality of the habitat since anthropic interference and occurrence of fires caused by humans frequently reach the limits or areas within the park. The species has an Area of Occupancy (AOO) smaller than 10 km 2 (B2), with only one known population in an area with continuous decline in habitat quality [ab(iii)]. Thus, according to IUCN (2019) criteria B2ab(iii), W. itambana must be categorized as Critically Endangered (CR). Therefore, it is important to make efforts to discover new populations for a better understanding of the plant’s biology and ecology. A recent analysis conducted by Machado & Versieux (2021) indicated that the other species of the genus, W. hatschbachii is severely threatened and its likely to go extinct in the near future due to habitat loss and climate change.

The Parque Estadual do Pico do Itambé region is considered an area of endemism in the center of Espinhaço mountain range ( Echternacht et al. 2011). Many species described for the park were considered local endemics but after the increase in the collections efforts along other areas of rupestrian grasslands new areas of occurrence were found, indicating that the range of these species was wider than previously assumed. This is the case of Vriesea medusa Versieux (2008: 713) and Lapanthus itambensis ( Versieux & Leme 2007: 130) Louzada & Versieux (2010: 500) described from the Parque Estadual do Pico do Itambé and later collected in the Parque Estadual do Rio Preto. Thus, it is possible that the distribution of W. itambana is wider than currently known to us.

Comments:— The genus Waltillia can be differentiated from Vriesea by the absence of petal appendages (vs. petals bearing appendages at the base), and petals almost five times longer than wide (vs. usually three times) and pollen showing a sulcus covered by a type of operculum (vs. insulae type) as well as its seeds with apical and basal appendages developed ( Alcantarea type).

The specimen described here ( Souza 295) was previously identified in the herbarium as Vriesea clausseniana (Baker) Mez (1894: 545) (Fig. 4A–B). Probably, characteristics such as simple inflorescence, with decurrent darkbrown floral bracts and large flowers caused this incorrect identification. Waltillia itambana can be differentiated from Vriesea clausseniana by the rosettes with lanceolate leaves ≤ 2.5 cm with acuminate apex (vs. broad leaves> 4 cm with a rounded apex), flower not secund at anthesis (vs. unilaterally secund flowers), longer than wide petals in an open fan like corolla (vs. short and wide petals in a campanulate corolla) (Fig. 4B). Rosettes with lanceolate leaves such as those of W. itambana , are not common in bromeliads with distribution in rupestrian grasslands, which tend to have subupright broader leaves or tubular shape rosettes, improving the capacity to hold water. Among the Vriesea species that occur in the rupestrian grassland, those with narrow-triangular leaves more like W. itambana are Vriesea longistaminea C.C. Paula & Leme (in Leme & Paula 2004: 27) (Fig. 4C–D) and Vriesea atroporpurea Silveira (1931: 3) . However, both species have a compound and lax inflorescence, with campanulate flowers that have shorter and wider petals than those of W. itambana .

FIGURE. Map indicating the population of Waltillia itambana (described here, black triangle) 61 km apart from the closest population of W. hatschbachii (black circle), both in the state of Minas Gerais, Brazil. Brown areas indicates Cerrado savanna domain and the green portion indicates the Atlantic Forest domain. The shaded parts indicate elevations above 900 m covered by rupestrian grasslands.

In relation to Alcantarea species , the genus Waltillia can be differentiated by its simple and congested inflorescence (vs. inflorescence generally compound or lax when simple), floral bracts decurrent on the rachis (vs. not decurrent), petals with tips slightly recurved at anthesis (vs. strongly recurved at anthesis), which are unappendaged (vs. bearing large appendages at the base), anther with introrse dehiscence (vs. anthers with extrorse dehiscence), pollen showing a sulcus covered by a type of operculum (Fig. 5A, B, E, F) [vs. pollen showing a sulcus without indumenta covering (Santos et al. 2018)], stigma convolute-blade II (Fig. 1E; Fig. 3G) (vs. conduplicate-erect or conduplicate-patent) ( Leme et al. 2017, Versieux & Wanderley 2021). Among the Alcantarea species with distribution in rupestrian grassland such as A. compacta Leme & O.B.C. Ribeiro (2010: 257) , A. duarteana (L.B. Sm.) J.R. Grant (1995: 13) and A. nanhoumii (Leme) J. R. Grant (1995: 13) , and A. recurvifolia Leme (2014: 75) none has an inflorescence structure similar to W. itambana , which makes the species described here quite unique ( Versieux & Wanderley 2021). Regarding the rosette shape alone, the new species is most similar to A. duarteana .

FIGURE. Waltillia itambana . A. Plant habit. B. Leaf. C. Upper peduncle bract. D. Floral bract. E. Sepal. F. Flower. G. stigma detail. H. Petal and antepetalous stamen. Illustrator: Samyra Furtado.

FIGURE. A–B. Vriesea clausseniana: A. Habit. B. Flower. C –D. Vriesea longistaminea: C. Rosette. D. Flower. E –F. Waltillia itambana: E. Rosette. F. Flower. Photographs : A–B by Talita M. Machado, C–F by Júlia A. M. Paiva.

FIGURE. Scanning electron microscopy (SEM) images of pollen grains of Waltillia itambana ( Souza 295). A–B. Polar distal view. C. Polar proximal view. D. Equatorial view (long axis). E. Equatorial view (short axis). F. Sulcus margin with reticulate ornamentation on the right, detail of the sulcus ornamentation like operculum on the left. Bars = 10µm.

The species here described can be included in Waltillia due to a combination of floral characters such as unappendaged petals (Fig. 3H), which are five times longer than wide, forming an open fan like corolla with curved tips (Fig. 1D); anthers presenting pollen sacs with introrse dehiscence (Fig. 1D–E) and pollen with the sulcus covered by a type of operculum (Fig. 5). In addition, the new species proposed here is ecologically similar to Waltillia hatschbachii , also growing in rock outcrops above 1500 m of elevation, close to water streams.

Conversely, W. itambana can be easily distinguished from the other species of Waltillia by the size of the plant, that has a longer inflorescence peduncle (ca. 174 cm) (Fig.1A). Unlike the grass-like rosette of W. hatschbachii , the new species has an infundibuliform rosette with suberect leaves (Fig. 1B, Fig. 4E). The leaves have narrower blades (ca. 2.5 cm wide), but the sheaths are wider (ca. 5.5 cm) and overlapping, featuring the accumulation of water. In addition, the inflorescence of W. itambana is densely flowered with dark-brown floral bracts that are decurrent on the rachis (Fig. 1C) and can be easily differentiated from the lax inflorescence with green bracts of W. hatschbachii . The flowers of W. itambana are not secund at anthesis opposing the unilaterally secund flowers of W. hatschbachii . The pollen can also be used to differentiate the two species in Waltillia . In W. hatschbachii the major part of the sulcus surface is covered by a type of operculum ( Leme et al. 2017, Santos et al. 2018), whereas in W. itambana this operculum occupies a smaller part of the sulcus and can be segmented (Fig. 5). This segmentation of the sulcus ornamentation can be divided into three parts like in Figure 5A, in two parts (Fig. 5E) or forming a single plate covering half of the sulcus surface (Fig. 5B).