Hippeastrum mauroi Campos-Rocha & Dutilh, 2018

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 : 96-98

Hippeastrum mauroi Campos-Rocha & Dutilh , sp. nov. ( Figs. 4 & 5 )

Hippeastrum mauroi is similar to H. puniceum and H. reginae ( Linnaeus 1759: 977) Herbert (1821: 31) but can be distinguished from both by its uniflorous inflorescence (vs. 2–4, except rarely one in H. puniceum ), different color pattern at the base of the tepals, the paraperigone devoid of fimbrae (vs. fimbrae present), and the style up to 1/2 of the perigone length (vs. 2/3 or more).

Type: — BRAZIL. Mato Grosso: Chapada dos Guimarães, área de Cerrado ralo próxima ao Parque Nacional da Chapada dos Guimarães ; florescimento em cultivo no Jardim Botânico Plantarum, 21 August 2013, A. Campos-Rocha & G. Bellozi 1215 (holotype UEC!) .

Geophytic perennial herb up to 40 cm tall at flowering. Bulb ca. 4–5.4 cm long, 4–5.2 cm diameter, subterranean, oval to round. Leaves 1–4, up to 28 cm long at flowering, 2.2–2.8 cm wide, lorate, tapered proximally, flat, suberect to prostate, apex obtuse or rounded, margins flat, midrib inconspicuous adaxially, somewhat prominent at the base abaxially, dark green adaxially, pale green abaxially. Inflorescence one flowered; scape up to 28 cm tall, erect, cylindrical, laterally compressed, hollow, greenish, sometimes with vinaceous pigmentation near the base; spathe bracts 2, 3.1–4.5 × 0.8–1.2 cm, free or fused proximally, apex acute, greenish, marcescent; bracteole 1, 3.2–3.6 cm long, subulate. Pedicel 2–3.2 cm long at anthesis, greenish. Perigone 9.4–10.5 cm long, campanulate; hypanthium tube 2–2.6 cm long, reddish, greenish at the very base, often with vinaceous pigmentation; paraperigone of a callose ring without fimbrae. Tepals in free portion reddish, internally greenish to yellowish-green at the base, together forming a circular design extending into the center of the tepals for up to 1/2 of their length with whitish pigmentation distally, occasionally with central greenish stripe abaxially for up to 1/2 of their length; outer whorl (sepals) wider than the inner (petals), obovate, apex acute with apicule sub-apical 2–4.5 mm long; upper 7.2–8 × 3.2–3.8 cm; lateral 7.2–8 × 2.8–3.8 cm; petals obovate to oblanceolate, apex acute with apicule inconspicuous or absent; lateral 7–7.8 × 2.5–3 cm, lower 7–7.7 × 1.4–2 cm. Stamens 6, of four different lengths, inserted at the mouth of the hypanthium tube, much shorter than limb segments; filaments declinate-ascending, free portion greenish proximally, reddish distally, upper episepalous 3–3.8 cm long, lateral episepalous 3.2–3.8 cm long, lateral epipetalous 4.2–4.8 cm long, lower epipetalous 4–4.6 cm long; anthers 3.5–5 mm long after anthesis, oblong to oblong-reniform, pollen yellow. Ovary 1–1.3 cm long, trilocular, oblong to obovoid, greenish. Style 4–5 cm long, much shorter than limb segments, declinate to slightly ascending, greenish proximally, reddish distally; stigma trilobed, vinaceous. Fruit and seed not seen.

Etymology: —The specific epithet is in honor of our friend Mauro Peixoto, who collected and introduced us to this and so many other plants new to science. Mauro has a unique knowledge about Brazilian native plants, a result of decades of study and observation in the field, having collaborated actively with various scientists over the years.

Distribution and habitat: — Hippeastrum mauroi is, as so far known, restricted to the municipality of Chapada dos Guimarães, Mato Grosso state ( Fig. 3 ). It was collected among rocky outcrops in pockets of accumulated organic material, in an area of cerrado ralo, near the boundaries of the National Park of Chapada dos Guimarães (PNCG). A second population was later found about 50 km distant in a similar environment, however no records were made of this population. Only H. elegans ( Sprengel 1815: 59) Moore (1963: 16) had been previously collected in the municipality of Chapada dos Guimarães.

Conservation status: — Hippeastrum mauroi is categorized as Critically Endangered based on the criteria B1ab(iii)+2ab(iii), due to the number of known locations (two) and decline in quality of the habitat, also based in criterion D, because the populations contain less than 50 mature individuals. Despite having been collected near the boundaries of the National Park of Chapada dos Guimarães, the species has not yet been located within the conservation unit.

Phenology: — Hippeastrum mauroi was observed in flower in habitat in July. In cultivation, it flowers from July to September.

Notes: — Hippeastrum mauroi resembles H. reginae , especially by the greenish-white color pattern at the throat, but can be distinguished by its uniflorous inflorescence, the paraperigone free of fimbrae, and the short style. The new species can also be considered similar to H. puniceum , a species of broad distribution on the South American continent, occurring in many different types of environments. Hippeastrum puniceum , however, with single exception, bears 2–4 flowers, a perigone tube that is abruptly declinate proximally, a circular pattern of yellowish to green at the throat, and a fimbriate paraperigone (only a single collection from Espírito Santo state has fimbrae occasionally absent from the paraperigone). Hippeastrum monanthum ( Ravenna 1969: 69) Meerow in Meerow et al. (1997: 18) was described with a uniflorous inflorescence and was later reduced to a subspecies of H. puniceum [ Ravenna 1981, but treated erroneously as Amaryllis belladonna Linnaeus (1753: 293) ].

Several other species of Hippeastrum occurring in the Brazilian Cerrado can bear only a single flower at times. Three of the four species of Hippeastrum endemic to the campo rupestre of the Serra da Canastra and recently described are characterized as mainly uniflorous: H. canastrense Dutilh & R.S. Oliveira in Oliveira et al. (2013: 39), H. roseoalbum R.S. Oliveira & Dutilh in Oliveira et al. (2013: 41) and H. sanfranciscanum Dutilh & R.S. Oliveira in Oliveira et al. (2013: 43). However, all have linear leaves, which distinguishes them vegetatively from H. mauroi . Hippeastrum glaucescens , a species widely distributed in the Cerrado Biome, may occasionally carry only one flower, but the perigone is much more strongly zygomorphic, and the upper sepal is much wider than the other two. The paraperigone of H. glaucescens consist of a ring of partially connate fimbrae. All four species from the Serra da Canastra have trifid stigma (vs. tri-lobed in H. mauroi ). The spathe bracts of H. mauroi can be fused for up to half of their length, a rare feature in Hippeastrum , but frequent in other genera of the tribe Hippeastreae which have singleflowered inflorescences ( Meerow & Snijman 1998).

Figures

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).

FIGURE 4. Hippeastrum mauroi. A. Inflorescence, frontal view. B. Inflorescence, lateral view. C. Lamina. D. Spathe bracts. E. Flower with perigone removed, showing stamens and style. F. Tepals: shape and apices. F1. Upper sepal. F2. Lateral petal. F3. Lateral sepal. F4. Lower petal. G. Longitudinal section of the ovary. H. Stigma. Drawn by Klei Sousa.

FIGURE 5. Hippeastrum mauroi. A. Plants flowering ex situ. B. Flower, lateral view. C. Flower, frontal view. A: A. Campos-Rocha & G. Bellozi 1215. Photos A: A. Campos-Rocha. B, C: M. Peixoto.