Hippeastrum lunaris Campos-Rocha & Meerow

Campos-Rocha, Antonio, Meerow, Alan William & Dutilh, Julie Henriette Antoinette, 2018, Two new critically endangered species of Hippeastrum (Amaryllidaceae) from the Brazilian Cerrado, Phytotaxa 360 (2), pp. 91-102 : 92-95

Hippeastrum lunaris Campos-Rocha & Meerow ( Figs. 1 & 2 )

Hippeastrum lunaris is similar to H. morelianum Lemaire (1845: 37) and can be separated readily by underground bulb (vs. exposed) and the paraperigone of free and loose fibrae (vs. fimbrae partially connate). It appears related to H. leucobasis ( Ravenna 1978: 90) Dutilh in Meerow et al. (1997: 18) but differs by the staminal filaments shorter than the perigone and its trifid stigma (vs. filaments exceeding the perigone and a capitate stigma in H. leucobasis ).

Type: — BRAZIL. Goiás: Colinas do Sul , campo sujo com mata inundável adjacente, área a ser inundada, 13° 43’ 16” S, 48° 17’ 27” O, 18 December 1996, L. B. Bianchetti 1502 (holotype CEN [photo!]; isotype UB!; UEC!) .

Geophytic perennial herb up to 1 m tall at flowering. Bulb subterranean in sandy-rocky soil. Leaves 1–5, up to 22 cm long at flowering, lorate, flat, erect, apex obtuse, margins entire, midrib inconspicuous adaxially, prominent abaxially, similarly green colored in both sides, occasionally with reddish to vinaceous pigmentation on the margins and near the midrib adaxially. Inflorescence 2–7 flowered; scape up to 88 cm long, 1–1.8 cm wide distally, erect, cylindrical, hollow, greenish to reddish, often vinaceous near the base or throughout its length; spathe bracts 2, 5.4–7.2 × 1.2– 2.1 cm, free or variably fused proximally on one side, apex acute, greenish to vinaceous, marcescent; bracteoles numerous, 2–5.4 cm long, lanceolate to subulate. Pedicel 3.8–5.2 cm long at anthesis, vinaceous. Perigone 9.8–12 cm long, funnelform-campanulate; hypanthium tube 0.4–1 cm long, reddish to vinaceous, occasionally with greenish pigmentation; paraperigone of fimbrae 0.5–2 mm long at the throat. Tepals often with the apex curved backwards, reddish in the free portion, internally with a yellowish-green central stripe at the base becoming lighter near the apex, eventually flanked by faint thin whitish striations, externally often with greenish to vinaceous pigmentation proximally; outer whorl (sepals) wider than the inner (petals), obovate, apex acute, occasionally rounded, with apicule subapical 2–5 mm long; upper 9–10.8 × 3–4 cm; lateral 8.7–10.7 × 2.8–4 cm; petals obovate to oblanceolate, apex acute with apicule inconspicuous; lateral 8.6–10.6 × 2.2–3.3 cm; lower 8.2–10.2 × 1.7–2.8 cm. Stamens 6, of four different lengths, inserted at the mouth of the hypanthium tube, shorter than the limb segments; filaments declinate-ascending, free portion reddish, occasionally yellowish to yellow-greenish near the base or up to 4/5 of its length, upper episepalous 6.5–8.6 cm long, lateral episepalous 5.4–6.6 cm long, lateral epipetalous 7.6–9.8 cm long, lower epipetalous 6.6–9.2 cm long; anthers 4–8 mm long after anthesis, oblong to oblong-reniform, pollen yellow. Ovary 0.9–1.2 cm long, trilocular, obovoid, vinaceous. Style 8.3–11.4 cm long, similar length or longer than limb segments, declinate-ascending, reddish, occasionally yellow-greenish to yellowish near the base or up to 4/5 of its length; stigma trifid, lobes 1–4 mm, occasionally of different lengths, whitish. Fruit and seed not seen.

Etymology: —The specific epithet refers to the Vale da Lua, to where the species is confined. The area is so named because of its rock formations along the banks of the ribeirão São Miguel, considered similar to lunar craters.

Distribution and habitat: —The currently known distribution of H. lunaris is restricted to a single location, in Chapada dos Veadeiros, in the north of the state of Goiás ( Fig. 3 ). The type locality was flooded with the construction of the Serra da Mesa dam, the largest reservoir in the country by volume of water when it opened in 1998 ( Thiengo et al. 2005), currently at less than 10% of its total storage capacity ( Borges 2017). A second population was located in the Vale da Lua, in the municipality of Alto Paraíso de Goiás; however, no specimens were collected in this area. The species occurs in areas of campo sujo (grassland with scattered low shrubs and isolated small trees) or cerrado ralo (a continuous herbaceous layer but trees and shrubs representing up to about 20% of the cover (see Ribeiro & Walter 1998, for more detailed definitions), near water courses or periodically inundated areas. The Chapada dos Veadeiros has an acknowledged high degree of endemism ( Munhoz & Proença 1998, Simon & Proença 2000, Munhoz & Felfili 2006, Watanabe et al. 2015), even though the local flora remains poorly known ( Munhoz & Felfili 2006, Simon et al. 2010). Four other Hippeastrum species are recorded from the region: H. glaucescens (Mart. ex Schultes & Schultes 1830: 813) Herbert (1837: 139) , H. goianum ( Ravenna 1974: 62) Meerow in Meerow et al. (1997: 17), H. leucobasis and H. puniceum ( Lamarck 1783: 122) Voss (1895: 1033) . Hippeastrum paradisiacum ( Ravenna 1981: 59) Meerow in Meerow et al. (1997: 18) was published from material collected in Alto Paraíso de Goiás, but is considered a synonym of H. glaucescens ( Dutilh & Oliveira 2015) .

Conservation status: — Hippeastrum lunaris should be categorized as Critically Endangered (CR) based on criteria B1ab(iii)+2ab(iii), due to the number of locations (one) and declining habitat quality, also based on criterion D, due to the small number of individuals. The only remaining known population is near the boundaries of the Chapada dos Veadeiros National Park (PNCV), although records for the conservation unit have not been located. The area of occurrence receives a large influx of tourists throughout the year, who have been known to collect bulbs. The locality also suffers from frequent and large-scale burning in dry periods, as does the National Park ( Fiedler et al. 2006, Tatagiba 2010) and private reserves in the surrounding area ( Lima 2013).

Phenology: — Hippeastrum lunaris under cultivation was collected in flower in August, but has been observed flowering in its natural habitat from September to December. Most photographic records that we have seen suggest a prevalence of flowering after fire, but we are not prepared to state an obligate fire ecology for this species.

Notes: — Hippeastrum lunaris is somewhat similar in floral morphology to H. morelianum , a species occurring in campo de altitude and campo rupestre vegetation, on rocky outcrops in Southeastern Brazil ( Oliveira 2012, Dutilh et al. 2013). In addition to important ecological differences, H. lunaris differs by always having the bulbs underground (vs. partially to fully exposed in H. morelianum ), bracts sometimes fused for half their length on one side (completely free in H. morelianum ) and a paraperigone of free and loose fimbrae (fimbrae partially connate in H. morelianum ). Hippeastrum lunaris usually produces a greater number of flowers per inflorescence (2–7 vs. 2, very rarely 4, in H. morelianum ). Hippeastrum lunaris can also be differentiated from H. leucobasis , a species described from the southwest of Goiás state, by the prolongation of the adaxial yellow-green stripe on the tepals for more than half their length (frequently for their entire length), androecium shorter than the perigone, and its trifid stigma. In H. leucobasis , there is a yellowish-green circle at the perigone throat with short, star-like prolongations for less than half the tepal length; the filaments are exerted from the perigone, and the stigma is capitate. Hippeastrum lunaris has some similarities in floral morphology to H. diniz-cruziae Dutilh & Semir in Oliveira et al. (2013: 41), a species endemic to Serra da Canastra in the state of Minas Gerais. It can be distinguished by its subterranean bulbs on sandy soil and perigone 9.8–12 cm long (vs. the bulbs situated between cracks in rocks, a perigone 4.8–8.1 cm long and a different coloration pattern in H. diniz-cruziae ). Finally, it differs from H. cipoanum ( Ravenna 1970: 86) Meerow (2010: 159) , a species restricted to Serra do Cipó of Minas Gerais, by its lorate leaves (linear in H. cipoanum ), in addition to 2–7 flowered inflorescences and longer perigone (1–2 flowers, with a 5–8 cm long perigone in H. cipoanum ).

Figures

FIGURE 1. Hippeastrum lunaris. A. Inflorescence. B. Flower, frontal view. C. Tepals: shape and apices. C1. Upper sepal. C2. Lateral petal. C3. Lateral sepal. C4. Lower petal. D. Flower with perigone removed, showing stamens and style. E. Detail of fimbriae of the paraperigone. F. Stigma. Drawn by Klei Sousa.

FIGURE 2. Hippeastrum lunaris. A, B. Flowering plants in habitat. C. Details of leaves and inflorescence. D. Detail of flower. Photos A: J. Costa. B–D: H. Moreira.

FIGURE 3. Distribution map showing records of Hippeastrum lunaris (diamonds; the white-filled diamond represents the remaining population. The type locality of H. lunaris was destroyed by flooding), and H. mauroi (circles).