Siqueiranthus cinereus Leme, Zizka, E. H. Souza & Paule 2022, comb. nov.
Creators: name: Leme, Elton M. C.
name: Zizka, Georg
name: Souza, Everton Hilo De
name: Paule, Juraj
name: De Carvalho, Jordano D. T.
name: Mariath, Jorge E. A.
name: Halbritter, Heidemarie
name: Ribeiro, Otávio B. C.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Bromeliaceae
Siqueiranthus
Siqueiranthus cinereus

description: Siqueiranthus cinereus (D.M.C. Ferreira & Louzada) Leme, Zizka, E.H. Souza & Paule, comb. nov.
Basionym:— Cryptanthus cinereus D.M.C. Ferreira & Louzada, Systematic Botany 45: 460. 2020. Type:— BRAZIL. Alagoas: Ibateguara, Sítio Duas Barras, 8 May 2019, D. Cavalcanti, E. M. de Almeida, A. Melo, F. G. Silva, W. T. C. C. Santos & V. B. V. Souza 921 (holotype: UFP!, isotypes: MAC, RB, UFRN, SP, NY, unavailable).
Description:— Plants andromonoecious, saxicolous, long caulescent usually by the successive growth of a single apical shoot, stems 18–160 cm long, 1.7–2.8 cm in diameter, rigid, erect to prostrate, propagation by a single shoot at the base of the inflorescence and by few shoots along the stem, rhizomes not detected. Leaves 30–49 in number, equally arranged along the stem, strongly coriaceous; sheath suborbicular to reniform-trapeziform, 2.8–3.5 × 4.4– 6 cm, yellowish and glabrous near the base, green or reddish and densely cinereous lepidote toward the base and mainly abaxially strongly corrugate, persisting on the older part of the stem, densely spinose distally; spines narrowly triangular, 0.5–3 mm long, 0.2–3 mm apart, straight, antrorse or retrorse, densely white lepidote; blade 17–57 × 4–4.7 cm, narrowly triangular-lanceolate, attenuate-acuminate, suberect to spreading or reflexed (mainly at anthesis), green or reddish-castaneous when fully exposed to sun, abaxial surface completely covered by a dense layer of cinereous trichomes obscuring the blade color, adaxial surface densely lepidote by cinereous trichomes obscuring to not at all obscuring the blade color, becoming partially glabrescent with age, margins straight to slightly undulate, densely spinose near the base to laxly spinulose toward the apex; spines triangular, 0.5–3 mm long, 2–14 mm apart, antrorse. Inflorescence compound, sessile, corymbose or a compact glomerulate spike, 4–6 cm long (petals not included), 4–4.5 cm in diameter, with perfect and staminate flowers in the lateral fascicles, bearing a distinct apical-central simple head of 19–25 staminate flowers; primary bracts foliaceous or subfoliaceous, the basal ones many times exceeding the fascicles, the upper ones abruptly reduced in size, slightly exceeding the fascicles, narrowly triangular, green or becoming rose to vinaceous at anthesis, forming an inconspicuous colorful ring around the inflorescence in contrast with the prevailingly cinereous-green color of its distal portion, both surfaces densely cinereous lepidote, margins straight to undulate, densely spinose near the base to laxly spinulose toward the apex; spine s 0.5–3 mm long, 1–10 mm apart, antrorse; fascicles 5–7 in number, with 2–7 perfect and/or staminate flowers, complanate, flabellate, 40–45 × 20–25 mm (petals excluded), subsessile to shortly stipitate, with 2–4 lateral sterile bracts; stipe subcomplanate, 5–6 × 4–5 mm. Floral bracts sublinear to narrowly triangular-lanceolate, cymbiform, densely and coarsely white lepidote toward the apex, hyaline to greenish-white near the base and green to rose toward the apex, margins entire or inconspicuously and sparsely denticulate, those in the fascicles 20–34 × 5–13 mm, strongly carinate to ecarinate, apex acute, those in the staminate flowers of the apical/simple part of the inflorescence 20–27 × 5–7 mm, ecarinate to obtusely carinate, apex acuminate. Flowers sessile, diurnal, fragrance not detected, the perfect ones 45–52 mm long (including the petals), the staminate ones 30–48 mm long (including the petals); sepals narrowly lanceolate, acuminate, thin in texture, carinate to obtusely carinate, whitish near the base, green to rose toward the apex, densely and coarsely white lepidote with brown-centered trichomes, obscuring the sepal color at the apex, entire, those of the perfect flowers 21–22.2 × 3–5 mm, connate at the base for (2.4-) 5–6 mm, those of the staminate flowers 16–22.2 × 3–5 mm, connate at the base for 4–5 mm; petals narrowly obovate to oblanceolate, rounded to slightly emarginate, free or connate for less the 1 mm (subfree), erect except for the suberect apex, forming a prevailingly tubular corolla, 20–26 × 4–6 mm, bearing well developed appendages as well as 2 conspicuous longitudinal callosities about reaching the midpoint of the filaments; appendages scutelliform with tendency to cupuliform, thick, 3–5 mm above the base, upper and lower margin inconspicuously and irregularly scalloped, not glandulose; stamens included, partially visible inside the corolla at anthesis; filament white, terete, unequal, 11–18 mm long, the antesepalous ones free, longer than the antepetalous ones, the antepetalous ones adnate to the petals for 1–3 mm; anther 2.5–5 mm long, base deeply bilobed, apex obtuse and inconspicuously apiculate, fixed at the base of the connective between the basal lobes (basifixed), not laterally compressed at anthesis, dehiscence introrse; pollen sulcate, spherical, ca. 55 µm, reticulate, reticulum with slightly flat muri and broad lumina decreasing in size towards the sulcus margins especially towards the apices, sulcus broad, without distinct margins, covered with exine elements partially forming a net. Style 20–25.5 mm long, completely reduced in straminate flowers; stigma simple-erect with tendency to simple-patent, white, lobes longer than broad, elliptic or narrowly obovate in outline, suberect, 2–2.2 × 1 mm, navicular, V-shaped with a central furrow, bearing regular and fine transversal grooves from the middle toward the margins and with a slightly undulate surface, margins inconspicuously crenulate, with sparse and irregular long filamentous white trichomes. Ovary trigonous, white, glabrous to inconspicuously and sparsely white lepidote with fimbriate trichomes, in the perfect flowers 15–19 × 6–8.2 mm, ovoid, in the staminate flowers 10–16 × 4–6 mm, cylindrical; epigynous tube 5–8 mm, narrow; ovules obtuse, 18–25 per locule in perfect flowers, fewer in number to absent in the staminate flowers; placentation apical. Fruits 18–25 × 7–8 (–9.2) mm, narrowly obovate to ellipsoid, trigonous, glabrous to inconspicuously white lepidote, white except the greenish or reddish-green distal portion, sepals in fruit persistent, stramineous, the distal portion often decaying, remnants 6–7 times shorter than the fruit length; seeds 10–20 per fruit, 2–3.5 (–4) × 1.5–3 mm, asymmetrical, subquadrate, subreniform or subtrapeziform, pale brown when mature, distinctly striate.
Distribution and habitat:— Siqueiranthus cinereus is only known from the type population, as a saxicole, growing at the top of a granitic outcrop in the Atlantic Forest domain in the municipality of Ibateguara, Alagoas state, Brazil (fig. 11.). The area is part of a small but rich fragment of vegetation located inside farms and isolated by surrounding pasturelands (fig. 11 F). It is accessible to horses, cows, and other domestic animals, which were seen eating leaves and inflorescences of S. cinereus, certainly causing an important impact on the reproduction and survival of its tiny population. Probably, this fragment will be destroyed in the coming years and completely occupied by pasturelands, despite its rich bromeliad community composed by endemic and even endangered species, like Aechmea catendensis Siqueira & Leme (Leme & Siqueira-Filho, 2006: 205), A. costantinii (Mez, 1916: 245) Smith (1970: 281), A. leptantha (Harms, 1929a: 786) Leme & Siqueira (2006: 213), A. nudicaulis var. nordestina Siqueira & Leme (Leme & Siqueira, 2006: 243), besides several tillandsioid species, to name a few. The investigation performed in the ecologically similar hills around the type locality did not reveal any subpopulation of S. cinereus (J.A. Siqueira pers. comm.).
The studied population at the type locality ‒ the only known one ‒ is limited in the number of plants, being composed by approximately 800 individuals in different stage of development, most of them wih mature size. Seedlings were not observed at the spot. The most part of the population is partially or completely shaded by shrubs and short trees of Melastomataceae, Clusiaceae, Myrtaceae, Rubiaceae, and Asteraceae, being intermingled with them. Without a strong enough root system to support the upright growth of the long-caulescent plants, S. cinereus grow propped up by the surrounding bushes (fig. 11 D). At the periphery of the vegetation island, the leaves of some individuals of S. cinereus, exposed to full sun, turn reddish.
Plotting the known occurrence of S. cinereus in Geocat software (Bachman et al. 2011), the obtained estimated extent of occurrence (EOO) is 0.051 km ², and the area of occupancy (AOO) is 8 km ², placing the species in the IUCN concept of being a critically endangered (CR) species. When its small area of occurrence is associated to the highly negative human pressure mentioned above, that affects S. cinereus, according to the criteria B1 [ab (i, ii, iii)] of the IUCN (2020) its critically endangered (CR) status is reiterated. So, the in-situ survival of this unusual species is uncertain, recommending extra conservation efforts to keep it alive at least ex-situ.
Etymology:—The epithet of this species name is a clear reference to the dense cinereous coverage of trichomes that characterizes it.
Distinctive characters:— Siqueiranthus cinereus is a unique species without close relationship with any known species of the “Cryptanthoid complex” in general or specifically from the region north of São Francisco river where it lives. Its uniqueness was highlighted in the protologue concerning leaf blade width and dense layer of cinereous trichomes (Ferreira & Louzada 2020), and it was then associated to the endemic Cryptanthus felixii Siqueira & Leme (Leme & Siqueira 2006: 285), which is morphologically and phylogenetically not related to it. Differences to Cryptanthus are indicated in the respective item above.
description: Published as part of Leme, Elton M. C., Zizka, Georg, Souza, Everton Hilo De, Paule, Juraj, De Carvalho, Jordano D. T., Mariath, Jorge E. A., Halbritter, Heidemarie & Ribeiro, Otávio B. C., 2022, New genera and a new species in the " Cryptanthoid Complex " (Bromeliaceae: Bromelioideae) based on the morphology of recently discovered species, seed anatomy, and improvements in molecular phylogeny, pp. 128-170 in Phytotaxa 544 (2) on pages 159-160, DOI: 10.11646/phytotaxa.544.2.2, http://zenodo.org/record/6503832