Polyspatha oligospatha Faden, 2011

Faden, Robert B., 2011, A third species of Polyspatha, an Africanendemic genus of Commelinaceae, PhytoKeys 3, pp. 9-20 : 10-13

Polyspatha oligospatha Faden sp. nov.

Latin

Polyspatha oligospatha Faden sp. nov. a Polyspatha paniculata foliis trichomatibus uniseriatis in pagina superiore instructis, spathis plerumque minus numerosis differt; a Polyspatha hirsuta pubesentia foliorum plerumque multo sparsa trichomatibus uniseriatis in pagina inferiore semper carentibus, spathis minus congestis minus numerosis minus pubescentibus et plerumque patentibus differt; et ab ambo ordinatione testae et anthesi mane differt. Type: Uganda, Zintengese [=Zintengeze], (Mabira), September 1922, R. A. Dummer 5531 (US!, holo, K!, iso).

Description.

Stoloniferous perennial with erect shoots 5-20(-30) cm tall; internodes puberulous with hook-hairs, very rarely also with short, uniseriate hairs. Leaves usually subclustered terminally on the flowering shoot, sheaths 0.8-1.5 cm long, puberulous with hook-hairs ( Tomlinson 1966), very rarely also with short, uniseriate hairs, ciliate at the apex with hairs to 3 mm long; lamina petiolate, elliptic or broadly elliptic to ovate or ovate-orbicular, rarely oblong-elliptic, 3-9(-11) × 2-4.5 cm, apex acute to acuminate (to abruptly acute or mucronate), base cuneate to broadly cuneate, margins planar to slightly undulate, scabrous, adaxial surface with scattered, patent, long, uniseriate hairs, abaxial puberulous with hook-hairs. Inflorescence a terminal, simple or compound thyrse 2-7 cm long, up to 7.5 cm wide, the compound thyrses composed of up to 4, closely associated, erect to patent or declinate, terminal and axillary (from the upper leaves) simple thyrses, none of the axillary thyrses perforating a leaf sheath, each simple thyrse consisting of a short peduncle and an elongate, zigzag, retrosely puberulous (with hook-hairs) axis, to which are attached 4-8 distichous spathes; spathes at first erect, then patent, rarely becoming deflexed against the thyrse axis, attached 3-11 mm apart, usually not overlapping the one below (on the opposite side) (occasionally slightly overlapping it), 6.5-10(-12) mm long, (3-)4-7(-9) mm wide (folded), apex acute to rounded, sometimes mucronate, or sometimes the proximal spathes acuminate, surfaces brown or brownish at maturity, at least along the midrib (folded edge), prominent longitudinal veins usually absent, surface cells (in the brown parts) lustrous, distinctly bead-like at 20 × or higher magnification, surfaces puberulous with hook-hairs, sometimes with short, uniseriate hairs along the midrib area, margins ciliolate with hairs usually all <1.5 mm long; cincinni ca. 2-3-flowered; bracteoles ovate, with a few short hairs on the margins. Flowers bisexual, 3.5-8 mm wide; pedicels 1-2.5 mm long, glabrous or sparsely puberulous; sepals free, lanceolate or lanceolate-oblong to ovate, 3-4.5 × 1-2.3 mm, puberulous with hook-hairs and short, uniseriate hairs, white or hyaline white, outer sepal hooded distally; corolla white, upper petals clawed, 5-7 × 2.5-3 mm, limb ovate, 2-3 × 2.5-3 mm, claw 3.5-5 mm long, lower petal linear to oblong, (2-)3-4.7 × (0.2-)0.8-1 mm; filaments of stamens and staminodes fused basally, glabrous, white; staminodes 3, posterior, equal, filaments 3-6 mm long, antherodes pointing forwards, V-shaped, yellow, the lobes divergent, oblanceolate, 0.6-0.8 mm long; fertile stamens 3, anterior, filaments subequal, but the medial slightly shorter than the laterals, filaments 4.5-8.5 mm long, anthers ovate-elliptic to elliptic, 1-1.7 mm long, yellow, dehiscence extrorse, pollen yellow; ovary sessile, obovoid, dorsiventrally flattened, ca. 1 mm long and wide, style exceeding the stamens, 5.5-8.5 mm long, white, stigma capitate, white. Capsules bilocular, bivalved, 2-seeded, broadly elliptic, 2.5-3 × 2.5-3 mm, sometimes constricted between the seeds, tan, apex emarginate, cells of the outer capsule wall ± isodiametric. Seeds el liptic in outline, 1.6-2.2(-2.5) × 1.3-1.5(-1.6) mm, testa radiately ribbed with (17-)18-23 prominent ribs, the ribs more or less knobby and transversely interrupted, surface tan, sometimes more or less exposed except for some darker brown, matted material between the ribs, sometimes mainly covered by this material except for the rib tops; embryotega semidorsal; hilum straight to slightly curved, 1/2 to 2/3 the length of the seed ( Figure 1 ; Plate 1: 3, 4 )

Distribution.

Ivory Coast, Cameroon, Republic of Congo (Congo-Brazzaville), Democratic Republic of Congo (Congo-Kinshasa), Sudan, Uganda ( Figure 2 ).

Habitat.

Understory in evergreen and semi-deciduous forests, forest relicts and other moist, shaded habitats in savanna, shaded cultivation, especially of cacao; ca. (15-)600-1220 m.

Chromosome number.

2 n = 28 (from Faden et al. 86/2 from Cameroon, cultivated at the Smithsonian Institution [Faden unpublished]).

Phenology and anthesis.

A total of 24 flowering collections of Polyspatha oligospatha have been seen, with specimens collected from all months except April and May. Anthesis occurs in the morning, based on the following records. Poulsen 1275 from Uganda, cultivated at the Smithsonian Institution Botany Research Greenhouse in 1997, had flowers open by 9:30 a.m. and fading at noon. Two collections from Cameroon, Hall & Kahn 075/93 and Keating 90-13 (both US), record this species as flowering in the morning and fading about noon.

Polyspatha oligospatha is easily recognizable but also readily overlooked, judging by its wide distribution and modest number of collections. It is distinctive because of its small stature, leaves with long, uniseriate hairs only on the adaxial surface, small inflorescences with small, well-spaced, often patent (i.e. not becoming deflexed) spathes whose surface is composed entirely or partly of lustrous, brown, bead-like cells, and seeds with numerous, radiating, knobby ridges that are transversely interrupted ( Figure 1: 7, 8 ; Plate 1: 3, 4 ).

Specimens seen.

Cameroon:

Adamoua Region: Near Kongi (10 km NW of Kimi-Bankim on Foumban - Banyo route), 27 June 1967, Letouzey 8742 (K, P, WAG) [two additional sheets of this collection at P are Polyspatha paniculata ]. Center Region: N’Kolbisson, ca. 8 km W of Yaoundé, 2 Dec. 1963, de Wilde & de Wilde-Duyfjes 1369 (P, WAG); same locality, 7 June 1964, de Wilde & de Wilde-Duyfjes 2647 (BR, K, WAG, YA); Nkolbisson, 8 km W of Yaoundé, Akouandoué Hill S of the town, 23 Jan.1986, Faden, Satabié & Mpom 86/2 (K, P, US, YA); Nkolbisson, 8 km W of Yaoundé, 3 km NW of the town, 24 Jan. 1986, Faden, Satabié & Mpom 86/22 (US); Mt. Febe, Yaoundé, 4 July1987, Manning 2166 (K, MO, WAG); Colline au N de Nkolbison (8 km W Yaoundé), 6 Feb.1963, Raynal & Raynal 9445 (P, YA). East Region: Boumba-Ngoko Dept., Moloundou Arrondissement, Lobeke swamp/savanna, adjacent to camp (site of an old sport hunting camp), 6 Feb.1993, Hall & Kahn 075/93 (K, P, US, YA, WAG). South Region: Ntem Departement, Ako’okas, 40 km SE of Ebolowa (by road), 30 June 1993, Keating 90-13 (US); same locality, 4 Aug. 1993, Keating 90-13 bis (K, P, US, YA); Rocheur de Mokomessi, 20 km NNW of Zoetélé, 35 km NNW of Sangmelima, 9 July1992, Letouzey 11465 (BR, K, P, YA); Ebolowa - Si I (W d’Ebolowa), basses pentes d’une colline dominant la ville, 9 Mar. 1963, Raynal & Raynal 10340 (P, YA).

Congo Republic:

Bassin de l’Alimo-Likoula, Réserve de Chasse de M’Boko, salime au bord de la Lekoli près du campement, 10 Aug. 1961, Descoings 9059 (P); Grand escarpement d’Odzala, au Nord de la cascade dorée, 27 Nov. 1996, Lejoly 96/961 (BR); Inter Bonga et Wesso (Sanga), Aug. 1899, Schlechter 12714 (BR) [mixture with Polyspatha paniculata ; K sheet of this number is pure Polyspatha paniculata ].

Democratic Republic of Congo:

Forestier Central (VI):en aval de Barumbu, 27 Oct. 1913, Bequaert 971 (BR); Panga, 19 Dec. 1913, Bequaert 1561 (BR); Uelé, Route Buta - Buna, 15 Oct. 1905, Seret 70 (BR) [2 sheets at BR, each with one plant of Polyspatha oligospatha (renumbered Seret 70A) and one of Polyspatha paniculata (renumbered Seret 70B); mapped as “Buta”)]. Ubangi-Uele (VII): Zongo (Ubangi), Nov. 1930, Lebrun 1729 (BR). Lacs Edouard et Kivu (IX): Vallée de la Semliki, a l’est de Beni, July 1929, Humbert 8796 (BR, P).

Ivory Coast:

Divo Forest, Oct. 1959, Aké Assi 5707 (K); North Divo Forest Reserve, 12 Oct. 1959, Fosberg 40559 (K, US).

Sudan:

Equatoria Province, Torit District: Tallanga Forest, 28 Dec. 1949, Jackson 1005 (BM).

Uganda:

Bunyoro (Masindi) District: Pabidi Forest, 14 Sep. 1995, Poulsen et al. 958 (C, US); Budongo Forest Reserve, Kanyo-Pabidi Block, 4 Feb. 1996, Poulsen et al. 1180 (C); Budongo Forest Reserve, between the Royal Mile and the Nature Reserve, close to the border of the Nature Reserve, at the campsite at the Nyabisabo River (gap), 4 Dec.1996, Poulsen et al. 1245 (US) & 1246 (K, MO); Budongo Forest, 17 July 1969, Stewart in EAH14170 (EA, K). Kigezi District: Just outside Queen Elizabeth Nat. Park, South Maramagambo Central Forest Reserve, 6.4-11.2 km up Kaizi-Bitereko road which is off the Katunguru-Ishsha road (Congo road), 18 Sep.1969, Faden et al. 69/1113 (BR, EA); South Maramagambo Central Forest Reserve, just outside Queen Elizabeth Nat. Park, 8 June 1969, Lock 69/155 (EA); Maramagambo Forest, 18 Sep.1969, Lye et al. 4117 (K). Mengo District: Zintengese [=Zintengeze], (Mabira), Sep. 1922, Dummer 5531 (K, US). Toro District: "Semliki District," 31 Oct. 1905, Daws 683 (K); Bwamba County, 1.2 km S of Sempaya, 23 Sep. 1969, Faden, Evans & Lye 69/1256 (EA); Bwamba, Buyayu-Sempayo road, Oct. 1929, Liebenberg 922 & 922A (K) [both are mixtures with Polyspatha paniculata ].

The three species of Polyspathia may be separated by the following key:

Figures

Figure 1. Polyspatha oligospatha Faden, sp. nov. 1. Habit. 2. Spathe with open flower, side view. 3. Flower, front view. 4. Flower, side view. 5. Stamen and staminode filaments, showing basal fusion. 6. Dehisced capsule. 7. Seed, dorsal view. 8. Seed, ventral. All from Poulsen 1275 (originally from Uganda; cultivated at the Smithsonian Institution). Illustration by A. R. Tangerini.

Plate 1. Seeds of Polyspatha species 1 - 2 Polyspatha paniculata Benth. 1 Seed, dorsal view 2 Seed, ventral view. (From Faden et al. 74 / 35 from Ghana, cultivated at Smithsonian Institution) 3 - 4 Polyspatha oligospatha Faden, sp. nov. 3 Seed, dorsal view. 4. Seed, ventral view. (From de Wilde & de Wilde-Duyfjes 2647 [BR] from Cameroon) 5 - 6 Polyspatha hirsuta Mildbr. 5 Seed, dorsal view 6 Seed, ventral view. (From Kahn 92 - 1 [US] from Cameroon).

Figure 2. Distribution of Polyspatha oligospatha Faden, sp. nov. The arrow indicates the location of the collection Letouzey 11465, which is atypcial for the species (see text).