Krenakanthus (Leme, S. Heller & Zizka) Leme, Zizka & Paule, 2022

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, Phytotaxa 544 (2), pp. 128-170 : 142-143

Krenakanthus (Leme, S. Heller & Zizka) Leme, Zizka & Paule , stat. nov.

Basionym:— Orthophytum subg. Krenakanthus Leme, S. Heller & Zizka, Phytotaxa 318: 75. 2017.

Type:— Orthophytum roseolilacinum Leme, Phytotaxa 205: 284. 2015 (holotype RB!).

Diagnosis:—This new genus differs from Orthophytum by leaves in most part chartaceous (vs. coriaceous or subcoriaceous), leaf blades glabrescent or glabrous (vs. usually distinctly lepidote at least abaxially) with undulate margins (vs. not undulate), flowers 4.2–5.5 cm long (vs. usually to 3 cm long), fragrant (vs. usually odorless), sepals connate (vs. free), petals broadly spathulate (vs. linearlanceolate to narrowly spathulate), spreading at anthesis (vs. erect to suberect with recurved apex only) and flaccidescent afterwards (vs. remaining erect), rose-lilac to lilac-purple toward the apex (vs. usually white or green), petal blades suborbicular (vs. ovate, obovate or elliptic), petal appendages thick, cupuliform (vs. echinatiform or sacciform, rarely cupuliform), stamens deeply included and not visible (vs. not deeply included, partially to distinctly visible), conduplicate-spiral stigma (vs. simple-dilated), and seeds laterally flattened (vs. not laterally flattened), with narrowly oblong raphe in cross section (vs. triangular in cross section).

Distribution and habitat:— Krenakanthus roseolilacinus , the single species in the genus, is only known from the type region, in the counties of Alvarenga and Conselheiro Pena, in the microregion of Aimorés which belongs to the mesoregion of the Rio Doce valley, Minas Gerais state (see Leme et al. 2017b, fig. 4). Plants are terrestrial, forming large and dense groups (fig. 8 A) in organic-rich, shallow soils accumulated on rocky surfaces in shady spots inside fragments of humid Atlantic Forest, from 255 to 810 m elevation (see Leme et al. 2017b, fig. 15 A).

Krenakanthus grows in the same region of two species of Orthocryptanthus ( O. arcanus and O. vasconcelosianus ), in the counties of Alvarenga and Conselheiro Pena, but it lives at lower elevated sites (i.e., 255 to 810 m elevation) as a typical Atlantic Forest dweller, not in sun-exposed sites associated to altitude fields/rupestral fields above 1000 m elevation, like O. arcanus and O. vasconcelosianus . It presents amazingly distinct morphological features from them (see respective item below).

As microendemic, with a reduced number of individuals in its known subpopulations and living in depleted and strongly fragmented Atlantic Forest habitat, it is considered a critically endangered (CR) species on the basis of the criteria “B1a” and “B2a” of IUCN (2020).

Etymology:—According to its protologue ( Leme et al. 2017b), Krenakanthus was named to honor the last descendants of the indigenous people native to eastern Brazil (pejoratively designated as “Botocudo” by the European settlers), known for their bravery, their comparatively taller and stronger physique, and by the wooden disks worn to expand their lips and ears. They were typical inhabitants of the Atlantic Forest of the states of Bahia and Espírito Santo, and the “Tupi” people called them “Aimoré” ( Pessoa 2009). After being decimated over the centuries, only the “Krenak” group survived, retaining their original language (“Borum”) and living between the cities of Conselheiro Pena and Resplendor, in Minas Gerais ( Seki 1992). This new genus was found in the county of Conselheiro Pena, not far from the territory of the remaining “Krenak”. Its single known species is comparatively tall, like the “Krenak”, with unique broad petals resembling expanded lips: with the Greek suffix “anthos”, Krenakanthus means the flower of the “Krenak” people.

Distinctive characters:—Positioned in the strongly supported (1 PP, 100 BS) clade “ Orthophytum s.l. ”, K. roseolilacinus is moderately supported (0.94PP) as sister of the remaining“ Orthophytum s.l. ” clade(i.e., Capixabanthus-Clavanthus-Orthophytum). It is a unique species without closer morphological affinity to any known species. Its general vegetative appearance characterized by the combination of long caulescent habit, and comparatively thin-textured leaves with undulate margins give it a very distinct appearance similar as some species of Rokautskyia which are not at all morphologically related to it. It also shares the caulescent habit and sessile inflorescence with three species of Orthophytum subg. Capixabanthus [i.e., O. pseudovagans , O. vagans , and O. zanonii Leme (2004: 72) ]. However, the caulescent habit is not an exclusive character of any genus, despite being important to characterize a group of species and segregating them.

In fact, the flower morphology of Krenakanthus is conspicuously distinct from Orthophytum subg. Capixabanthus in all aspects, except for the similar cupuliform petal appendages. Despite other differences in flower features, its thick, cupuliform petal appendages are also observed in O. foliosum Smith (1941: 58) , O. rubiginosum Leme (2005: 158) , and O. zanonii , while the sacciform type is noticed in O. compactum Smith (1966: 462) and O. vagans . Orthophytum pseudovagans has both cupuliform and sacciform petal appendage types.

It is important to highlight the unique combination of flower, fruit, and seed morphology and anatomy features of K. roseolilacinus , which distinguishes it from all other “Cryptanthoid” genera, such as sepals distinctly connate, petals with a very narrow proximal portion in contrast with the much broader spreading blade (fig. 8 D), the deeply included stamens not visible at anthesis (figs. 8 B, E), the conduplicate-spiral stigma type (fig. 15 J), fruits obtusely angulose, yellowish toward the apex, and the long and narrow (2–3 × 0.7–1 mm), slightly to distinctly curved seeds (fig. 18 O), which are laterally flattened, bearing fleshy, narrowly oblong raphe in cross-section (see item discussion above), not detected in any other Cryptanthoid species.

In general, Krenakanthus differs from Orthophytum subgg. Orthophytum , Capixabanthus, and Clavanthus by having leaves that are for the most part chartaceous (vs. coriaceous or suboriaceous), leaf blades glabrescent or glabrous (vs. usually distinctly lepidote at least abaxially) with undulate margins (vs. not undulate), inflorescence sessile (vs. usually on a distinct peduncle, except for three species of Orthophytum subg. Capixabanthus mentioned above, and members of Sincoraea ), flowers 42–55 mm long [vs. usually to 30 mm long, except for the outlier O. macroflorum Leme & M. Machado (2005: 171) with 50–65 mm long flowers], fragrant (vs. scentless), sepals connate (vs. free), petals broadly spathulate (vs. linear-lanceolate to narrowly spathulate), spreading at anthesis (vs. erect to suberect with recurved apex) and flaccidescent afterwards (vs. remaining erect afterwards), rose-lilac to lilac-purple toward the apex (vs. usually white or green), petal blades suborbicular (vs. ovate, obovate or elliptic), petal appendages cupuliform (vs. echinatiform, sacciform or rarely cupuliform in Orthophytum subg. Capixabanthus ), stamens deeply included and not visible (vs. not deeply included, partially to distinctly visible), and the conduplicate-spiral stigma (vs. simple-dilated, simple-erect or simple-patent).

Despite not morphologically related to Krenakanthus , Rokautskyia reveals a highly supported sister position in relation to the whole “ Orthophytum s.l. ” clade (i.e. Capixabanthus-Clavanthus-Krenakanthus-Orthocryptanthus-Orthophytum ) in which the two accessions of Krenakanthus from distinct subpopulations are included. Similarities are fragrant flowers and the broadly spathulate petals with suborbicular blades spreading at anthesis, and the shaded Atlantic Forest habitats. Differences are striking such as the rose-lilac to lilac-purple petals (vs. white) with cupuliform appendages (vs. exappendiculate), the stamens deeply included and not visible (vs. not deeply included and at least partially visible), and the conduplicate-spiral stigma blade (vs. simple-imbricate).

A full description of Krenakanthus roseolinacinus , here provided as a descriptio generico-specifica [Shenzhen Code, art. 38.5; Turland et al. (2018)], is presented in the sequence and the differences from Orthocryptanthus are discussed in the respective item below

Species: — Krenakanthus is a monotypic genus.