Hohenbergia rohan-estyi Proctor, Aguirre-Santoro & K. Campbell, 2016

Aguirre-Santoro, Julián, Campbell, Keron C. St. E. & Proctor, George R., 2016, A new species of Hohenbergia (Bromeliaceae) endemic to the Dolphin Head Mountains in western Jamaica, Phytotaxa 247 (2), pp. 133-137 : 134-136

Hohenbergia rohan-estyi Proctor, Aguirre-Santoro & K. Campbell , spec. nov. ( Fig. 1A–L ).

Type:— JAMAICA. Hanover Parish: road between Askenish and Dolphin Head, towards east side of the Dolphin Head Mountains , 305 m, 18º22’43.6” N, 78º9’7.6” W, 3 July 2012, J. Aguirre-Santoro, K. Campbell & R. Esty 1813 (holotype IJ! , isotypes NY! , US! ).

Hohenbergia rohan-estyi differs from the very similar H. negrilensis by its much longer stipes (19–39 mm vs. 2–8 mm long) and less numerous flowers per spike (18 to 35 vs. 50 to 60 flowers per spike). Hohenbergia rohan-estyi also resembles H. caymanensis and H. laesslei but mainly differs from them because of its more numerous flowers per spike (18 to 35 vs. 12 to 18 flowers per spike).

Plant an epiphyte, cespitose, flowering 150 cm tall, short caulescent; rosette broad, forming phytotelmata. Leaves 93–121 cm long, coriaceous; sheath conspicuously differentiated from the blade, oblong to elliptical, 15–26 × 8.5–17 cm, white to pale brown, lepidote on both surfaces, serrulate; blade lingulate, 73–94 cm long, 8.5–13.5 cm wide at the base, 8–11.5 cm wide in the middle, green, surfaces smooth, lepidote abaxially, glabrescent adaxially, blade margin serrate, the teeth evenly distributed along the margins, hook-shaped, irregularly oriented, green to castaneous, 6.3–11 mm long, blade apex obtuse to rounded, mucronate. Inflorescence central, erect to inclined; peduncle almost completely exposed out of the rosette, stout, rigid, 33–75 cm long, 7–14 mm in diameter, green, floccose, internodes between the central bracts 2.3–4 cm, internodes between the apical bracts 1.5–2.2 cm; peduncle bracts longer than the internodes, marcescent, membranaceous, nervose, light green, the central bracts erect, imbricate, lanceolate, 8–12.5 × 1–1.8 cm, sparsely floccose, entire, occasionally serrulate, apex acuminate, the apical bracts suberect, imbricate, lanceolate, 9.5–14 × 0.8–1.6 cm, sparsely floccose, entire or occasionally serrulate, apex attenuate; fertile portion of the inflorescence a panicle, conical, 39–78 cm long, 8–17.5 cm wide at the base, 1-divided or occasionally 2-divided in the lower branches, axis of the inflorescence straight, green, 35–74 cm long, 4–8 mm in diameter, floccose to sparsely floccose. Primary bracts like the peduncle bracts, gradually diminishing in size towards the apex of the inflorescence, reclined to descending, marcescent, membranaceous, nervose, longer than the branches; the basal bracts lanceolate, 9–13.7(–16) × 0.8–1(–1.7) cm, light green to cream, floccose to glabrescent, entire, apex attenuate; the apical bracts lanceolate, 1.1–2.4 × 2.8–3 cm. Branches of the inflorescence 43 to 52(–83) in number, polystichous. Spikes ovoidal to cylindrical, 2.1–5.8 × 1–1.8 cm; stipe exposed, 19–39 mm long, 1.8–3 mm in diameter, terete, floccose to glabrescent. Floral bracts gradually diminishing in size towards the apex of the spike, partially enfolding the ovaries, imbricate at the early stages of development, turning slightly divergent with the flowers at maturity, subconcave, coriaceous, ovate, 3.2–8 × 3.6–6.5 mm, green to cream, nervose, ecarinate, sparsely floccose, minutely serrulate, occasionally entire, apex acuminate, bearing a short mucro 1.5–5.8 mm long. Flowers 18 to 35 per spike, polystichously arranged, suberect to divergent, 3.2–8 mm long, sessile. Calyx dorsiventrally compressed; sepals basally connate, coriaceous, asymmetrical, with one of the margins much more extended than the other, triangular-ovate (excluding the extended margin), 3.5–4.7 mm × 2.6–3.6 mm, the narrow side 0.6–1.1 mm wide, the extended side 1.8–2.7 mm wide, green, yellow, or cream, surface smooth, the adaxial sepals carinate, the abaxial sepal ecarinate, floccose to glabrescent, entire, apex mucronate, mucro 1.1–2.2 mm long. Corolla sub-tubular; petals free, membranaceous, spathulate, 11.2 × 3 mm, white, glabrous, entire, apically spreading, apex acute; petal appendages two, flanking the antepetalous stamens, originating at 2.5 mm from the petal base. Stamens included, the antepetalous stamens partially adnate to the petals; filaments flattened, 7.3 mm long, 0.3 mm in diameter, white; anthers dorsifixed, sagittate, 3.1 × 0.7 mm, white, apiculate. Pistil exceeding the stamens; ovary subovoidal, dorsiventrally compressed, 3.1 mm long, 4.5 mm in diameter, green, glabrescent to sparsely floccose, placentation apically-axile, epigynous tube 0.3 mm long. Style cylindrical, 11.6 mm long, white; stigma conduplicate-spiral, white, 1.3 mm long. Ovules more than 30 per ovary, ovoidal, unappendaged. Pollen biporate, foveolate. Fruit subovoidal, dorsiventrally compressed, 9.4–9.8 mm long, 4.8–6 mm in diameter, cream, glabrous, with the sepals persistent, but not fleshy. Seeds club-shaped, 2.1 × 0.7 mm, reddish.

Etymology:— This species was named in honor to Rohan Esty, who made part of the team that collected the type specimen.

Distribution, habitat, and phenology:— Hohenbergia rohan-estyi is endemic to northwestern Jamaica at 20–370 m elevation ( Fig. 2 ). It grows in mesic forests on limestone formations in the region of the Dolphin Head Mountains. It can be found on exposed limestone hilltops as well as in lower hillside elevations in the Dolphin Head range. Collected in flower from July to November.

Conservation status:— Hohenbergia rohan-estyi is categorized here as Critically Endangered (CR, B1a; IUCN 2001) because it has an extent of occurrence of less than 100 km 2 and only occurs in the Dolphin Head Mountains, a protected area surrounded by rapidly growing urban development. Areas within and surrounding the Dolphin Head Mountains are traditionally known for hillside farming which could potentially have an adverse effect on the small populations of H. rohan -estyi through improper farming practices. Other practices such as timber and fuel wood extraction also have negative impacts on the forest where H. rohan-estyi grows. Generally, epiphytes are greatly affected because of the twinning effect of direct impacts such as land clearing and indirect impacts such as timber and fuel wood extraction where the trees are hosts of these plants.

Taxonomic comments and affinities:— Hohenbergia rohan-estyi is similar to H. caymanensis Britton ex Smith (1935: 150) , H. laesslei Smith (1956: 52) and H. negrilensis Britton ex Smith (1935: 151) because of its sublax branches of the inflorescence that fully expose the inflorescence axis; basal primary bracts much longer than the branches; acuminate to broadly acute and long-mucronate floral bracts; and long-mucronate sepals. It can be easily separated from H. negrilensis by its much longer stipes (19–39 mm vs. 2–8 mm long) and less numerous flowers per spike (18 to 35 vs. 50 to 60 flowers per spike). Hohenbergia rohan-estyi mainly differs from H. caymanensis by its longer stipes (19–39 vs. 6–18 mm long), white corollas (vs. green), and longer and broader petals (11.2 × 3 mm vs. 8–9.5 × 1.2 mm). Hohenbergia rohan-estyi differs from H. laesslei by its medial bracts of the peduncle longer than the internodes (vs. shorter), shorter stipes (19–39 mm vs. 40–42 mm long), more numerous flowers per spike (18 to 35 vs. 12 to 18 flowers per spike), and narrower floral bracts (3.6–6.5 mm vs. 7–9.8 mm wide). Finally, the other two species of Hohenbergia endemic to the Dolphin Head Mountains, H. brittoniana and H distans , can hardly be mistaken with H. rohan-estyi because of their unusually long stipes of the spike and short-mucronate floral bracts.

In addition to the diagnostic morphological characteristics that separate Hohenbergia rohan-estyi from H. caymanensis , H. laesslei and H. negrilensis , its geographic distribution does not overlap with any of them. First, H. caymanensis only occurs in Grand Cayman and Providencia Island in Colombia. Second, H. laesslei is endemic to the central region of the Cockpit Country of Jamaica. Lastly, as well as H. rohan-estyi , H. negrilensis is endemic to western Jamaica; however, the latter does not occur in the Dolphin Head Mountains and it is commonly found near coastal areas at lower elevations.

ADDITIONAL SPECIMENS EXAMINED. JAMAICA. Hanover Parish: road between Kingsvale and Retirement. Western slopes of Dolphin Head , 294 m, 18º22’32.7” N, 78º10’41.9” W, 4 July 2012, Aguirre-Santoro et al. 1816 ( IJ, NY, US); Below Cabarita River bridge, 0.3 miles north of Flower Hill P.A , 182–213 m, 8 August 1965, Proctor 26595 ( IJ); Retirement Mountain area of Dolphin Head Forest Reserve , 183–366 m, 30 January to 27 February 2001, Proctor 51773 ( IJ); slopes E. of Dolphin Head above Askenish , 275–335 m, 8 December 2001, Proctor 52037 ( IJ); Retirement Mountain area, W. side of Dolphin Head Forest Reserve , 183–305 m, 12 November 2006, Proctor 52581 ( IJ); Retirement Mountain area of Dolphin Head Forest Reserve , 183–305 m, 10 January 2007, Proctor 52588 ( IJ). Westmoreland Parish: 1 mile northwest of Frome , 23 m, 19 November 1955, Proctor 11157 ( IJ, US) .

Figures

FIGURE 1. Hohenbergia rohan-estyi. A. Inflorescence. B. Infructescence. C. Branch showing stipe and flower. D. Stipe and spike of the infructescence. E. Sepals. F. Flower in cross section showing the sepal arrangement. G. Petal and antepetalous stamen. H. Seed. I. Petal appendages. J. Dorsal view of the anther and filament insertion. K. Pollen. L. Apical portion of the style and stigma. (A–L: Aguirre-Santoro 1813. Photos of living specimens: J. Aguirre-Santoro).

FIGURE 2. Geographic distribution of Hohenbergia rohan-estyi.