Hohenbergia alba B.P. Cavalcante, E.H. Souza & Versieux, 2024

Hohenbergia alba B.P. Cavalcante, E.H. Souza & Versieux , sp. nov. ( Figs. 1–2 View FIGURE 1 View FIGURE 2 )

Diagnosis: — Hohenbergia alba is closely related to H. blanchetii , but easily distinguished by its broader yet smaller leaf blades (38–50 × 20–24 cm vs. 90–120 × 14–16 cm), pink (vs. green) ovoidal inflorescence (widely pyramidal), delicate and thinner peduncle (ca. 1 cm vs. 2 cm), flower size (ca. 13 mm long vs. 7–9 mm), white-colored and patent to ascendant petal blades (vs. lilac and reflexed).

Type:— BRAZIL. Bahia: Itamaraju, road that connects Itamaraju to Porto Seguro, in a cacao plantation near Itamaraju downtown, ca. 123 m elevation, 16°59’47.3”S 39°33’04.9”W, 25 May 2019, E. H. Souza & B. P. Cavalcante 61 (Holotype HURB! isotype: ESA! and UFRN!).

Plant epiphytic, 100–125 cm tall when flowering, rarely propagating by basal shoots. Leaves ca. 18 in number, arcuate to spreading, forming an open crateriform rosette 40–55 × 70–100 cm; leaf sheath 21–25 × 14–17 cm, elliptic, sparsely white lepidote on both sides, light castaneous except for the green distal part, stiff coriaceous, margins entire; leaf blade 38–50 × 20–24 cm, linear-oblong to lingulate, broadly canaliculate, apex cuspidate ending in a rigid but not spinose apex ca. 8 mm long, conspicuously brownish contrasting with the basal green portion of the blades, coriaceous, sparsely white-lepidote abaxially, margins spinulose, pale red, marginal spines black, rigid, very close to each other. Peduncle 45–60 cm long, ca. 10 mm diameter, erect, stiff, pink, white lanate, covered by its bracts; peduncle bracts 15–18 × 1.5–1.9 cm, lanceolate-aristate, brownish-stramineous, densely imbricate, exceeding the internodes and concealing the peduncle, glabrous. Inflorescence fertile part 43–65 cm long, 50–70 cm in diameter at its widest portion, paniculate, ovoidal, 3-4-branched, 2-branched distally, erect, pinkish stipes and rachis, densely white-lanate; primary bracts 4.5–6.2 × 1.4–1.7 cm, resembling the peduncle bracts in shape and color, but smaller, exceeding the sterile base of the branches; primary branches 24–34 cm long, the stipes 3–7 cm, divergent to spreading, densely white-lanate, with short-stipitate to sessile secondary branches, laxly and polystichously arranged along the reproductive axis; secondary bracts ca. 2 × 1.4 cm, elliptical, apex acuminate, resembling the primary bracts in color but smaller, shorter than the branches; secondary branches 6–10 cm long, distinctly stipitate to sessile, stipes (0–) 2–3 cm long, bearing sessile spikes at the distal portion; tertiary bracts resembling the primary and secondary bracts but smaller, ca. 1 cm long, shorter than the branches; spikes 2.5–4 cm long, short globose, 5–11-flowered; floral bracts ca. 4 × 11 mm, green, widely triangular-ovate and convexly embracing the ovary, caudate, nerved, margins entire, covered by white and blackish lanate indument, surpassing the sepals in length. Flowers ca. 13 mm long, sessile, organized in a strobilar shape, odorless; sepals 2–3 × 5–7 mm, green, triangular-ovate, margins entire, apex acuminate and slightly spinescent, asymmetrical with a thin marginal wing equaling the spinescent apex, connate at the base (ca. 25% of the sepal length), covered by an inconspicuous white and blackish lanate indument; petals 10–13 × 3–6 mm, spatulate, base erect and blade spreading towards the apex, margins entire, free, white, nerved, apex short apiculate, bearing 2 basal and fringed appendages at the base; stamens 4–5 mm long, emerging through the corolla; filaments 2–4 mm long, white, complanate; anthers 1–2 mm long, dorsifixed, apex apiculate; ovary 3–4 × 10 mm, green, wide-ovoidal, placentation axial; ovules caudate with a prominent chalazal appendage, ca. 0.4 mm long, epigynous tube inconspicuous; style 8–9 mm long, white, erect, exceeding the stamens, exposed by the spreading petals; stigma conduplicate-spiral. Fruit ca. 12 × 12–13 mm, bluish when ripe; seeds 1–1.5 mm, nearly ellipsoid, brownish.

Etymology: —The specific epithet “ alba ” refers to the white ( “alba ”) color of the petals, a rare trait for Hohenbergia .

Distribution and habitat: — Hohenbergia alba is an epiphyte in the canopy, growing on trees that shade cacao plantations, but never on cocoa trees, along the extreme south of Bahia, in the Itamaraju municipality. It shares its habitat with other Hohenbergia species, easily observed throughout the highways that connect Itamaraju to Porto Seguro, or in the edge of forests in this region.

The region is characterized by a hot and humid climate, typical of coastal humid forests, making it a hotspot for various bromeliad species, including representatives from different genera. However, within this habitat, only H. halutheriana Leme (2013: 299) and H. itamarajuensis Leme & Baracho (1999: 78) are observed sympatrically, being very distinct from H. alba . Hohenbergia halutheriana stands out due to its larger size and the red inflorescence with green spikes, while H. itamarajuensis is recognized by its pedunculate inflorescence with long-stipitate branches with a single apical spike (a thorough comparison can be found in Table 1).

Phenology: —Specimens were seen flowering, in cultivation, from November through February, at the Greenhouse of Centro de Energia Nuclear na Agricultura (CENA/USP) – Piracicaba/SP.

Conservation status: — The species is so far restricted to the coastal Atlantic Forest in the southernmost region of Bahia, within the municipality of Itamaraju. Its occurrence coincides with cacao plantations and numerous bromeliads are observed in forest along the highway. By plotting the known occurrences of this species, we estimate its extent of occurrence (EOO) to be approximately 1,684.5 km ², and the area of occupancy (AOO) to be 32 km ², classifying it as Endangered (EN). Consequently, we propose that this species be treated as an Endangered species (EN B2b (i, ii, iii, iv), following the IUCN criteria guidelines (IUCN, 2020).

Observations: — Hohenbergia alba is among the several giant Hohenbergia species inhabiting the coastal region of Bahia. It shares morphological similarities, particularly with H. blanchetii Mez (1891: 267) . Hohenbergia alba can be readily distinguished by its white petals, which is an uncommon trait within the genus and has only been observed in H. bellemii Smith & Read (1976: 438) , H. ituberaensis Cavalcante, Souza & Versieux (2020: 120) , H. littoralis Smith (1940: 33) , and H. viridorubra Leme (2013: 305) . (detailed comparison in Table 1).

In sympatry with H. alba , H. halutheriana , and H. itamarajuensis exhibit significant similarities during vegetative growth, particularly in their rosette structure, however at flowering they are easily distinguished (see detailed comparison in Table 1).