Paracephaelis capitulifera De Block 2022, sp. nov.
Creators: name: Block, Petra De
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Paracephaelis
Paracephaelis capitulifera

description: Paracephaelis capitulifera De Block sp. nov.
urn:lsid:ipni.org:names:77260706-1
Figs 1J–K, 7
Diagnosis
Differing from Paracephaelis sericea by having shorter stipular sheaths and longer awns (sheaths 8–13 mm and awns 1.5–4 mm vs sheaths 8–30 mm and awns 1–2 mm long), more secondary veins on each side of the midrib (10–15 vs 8–10), capitate inflorescences (vs not capitate), longer bracteoles (3–3.5 mm vs 1–2 mm long), and longer calyx tubes and lobes (tube 3–8 mm and lobes 1–2.5 mm vs tube 2–5 mm and lobes 0.5–1.5 mm long).
Etymology
The species epithet is based on the capitate inflorescences.
Type material
MADAGASCAR – Antananarivo Province, Analamanga Region, Ankazobe District • forêt d’Ambohitantely, jardin botanique; 1464 m a.s.l.; 6 Feb. 1999; fr; De Block & Rakotonasolo 736; holotype: BR [BR0000022757661]; isotypes: BR [BR0000022757616], BR [BR0000022757623], G, K, MO, P, TAN, TEF, WAG.
Other material studied
MADAGASCAR – Antananarivo Province, Analamanga Region, Ankazobe District • forêt d’Ambohitantely, sur le Tampoketsa d’Ankazobe; 1600 m a.s.l.; 27 Feb. 1966; fr; Capuron 24569 bis-SF; P, TEF • ibid.; 25 Nov. 1968; fl; Capuron 28271-SF; BR, P, TEF • Manankazo, along RN 4; 1574 m a.s.l.; 17 Feb. 1999; fr; De Block & Rakotonasolo 831; BR, G, K, MO, P, TAN • forêt d’Ambohitantely; 24 Feb. 1945; fr; Homolle & Boiteau D3; BR, P • Ambohitantely Reserve, along south limit of reserve; 1603 m a.s.l.; 13 Feb. 2018; fr; Razafimandimbison, Razafindrahaja, Atalahy & Swenson 2139; BR, MO n.v., P online, S n.v., TAN n.v. – Renivohitra District • parc botanique et zoologique de Tsimbazaza, arboretum; 1200 m a.s.l.; 19 Jan. 1975; fl; Croat 28780; K, MO. – Vakinankaratra Region, Antanifotsy District • Ambatotsipihina, Tsinjoarivo, Ambatolampy; 1300 m a.s.l.; 21 Nov. 1949; fl; coll. ignot. 1035-SF; P, TEF. – Fianarantsoa Province, Amoron’i Mania Region, Ambatofinandrahana District • commune Itremo, forêt gallerie d’Antsirakambiaty; 1594 m a.s.l.; 12 Dec. 2004; fl; Andriamihajarivo 267; MO n.v., P online • Itremo massif, near Itremo, 213 km SW of Antananarivo; 1650 m a.s.l.; 30 Oct. 1997; fl, fr; Davis, Andriantiana, Gower & Malcomber 1018; BR, K, P, TAN • montagnes W d’Itremo, W de Betsileo; 1500– 1700 m a.s.l.; 18–22 Apr. 1955; fr; Humbert 28298; BR, P • Itremo, Antsirakambiaty; 18 May 2005; st; Rakotonasolo & Rakotoarinivo 1014; BR, K, TAN • Itremo, 40 km en voiture W d’Ambatofinandrahana, Ianasana, dans une grande vallée (N-S) 25 km (vol d’oiseau) W du pont d’Ianasana; 1500–1610 m a.s.l.; 8 Apr. 1998; fl; Randrianaivo, Birkinshaw, Rakotomamonjy, Andriantiana & Randrianasolo 171; BR, K, MO. – Ambositra District • forêt de Kijole, Mangatanaboampy; 14 Feb. 1952; fr; coll. ignot. 5218- SF; P, TEF.
Description
Shrub to 5 m tall or tree to 10 m tall with dbh to 20 cm; pubescence tawny. Young shoots brown or reddish brown, densely covered with short erect hairs; older branches brown to greyish brown, flaking, glabrescent but pubescence remaining for a long time. Petioles 5–15 mm long, densely covered with short erect hairs. Leaf blades elliptic, ovate or rarely obovate, 6–14 × 2.5–7 cm, coriaceous and often somewhat bullate (when dried), drying brown to dark or blackish brown above and somewhat paler below, upper surface glossy, both surfaces densely covered with short erect hairs but pubescence on midrib and secondary veins often more appressed; base cuneate to attenuate; tip acuminate with acumen 0.3–1.5 cm long; domatia absent; 10–15 secondary veins on each side of midrib, often somewhat impressed above, raised below; higher order venation visible on both surfaces, often somewhat impressed above (especially towards the tip or the margin of the leaf), somewhat raised below. Stipules ovate to triangular with needle-like awn, keeled, outer surface densely covered with short erect hairs, inner surface glabrous with 2–3 rows of colleters at the base; sheath 8–13 mm long; awn 1.5–4 mm long; brown or orange-reddish mucus often present on youngest stipule pair, sometimes extending onto young inflorescences. Inflorescences sessile, capitate, 2–7.5 × 1–4.5 cm, with 12 to numerous flowers; inflorescence parts densely covered with short erect hairs; first order axes 0.2–2 cm long; second order bracts with stipular parts broadly triangular, <1 cm long, foliar parts broadly triangular and vaulted, or, more rarely, trilobed (with lateral lobes much smaller than central lobes), single or central lobe up to 1 cm long, tips acuminate; higher order bracts identical but stipular parts reduced or absent, foliar parts 4–7 mm long; bracteoles at base of ovary, opposite, stipular parts absent, foliar parts broadly triangular, 3–3.5 mm long, tips acuminate. Flowers sessile. Calyx densely covered with short erect hairs outside, inner surface densely covered with minute appressed hairs all over but most dense at the base; tube 3–8 mm long, with faint longitudinal ribs (when dried); lobes ovate or triangular, 1–2.5 mm long, keeled, margins ciliate, tips acuminate and often reflexed. Corolla tube ca 13 mm long, inner surface unknown; lobes ca 5 mm long. Stamens, style and stigma unknown. Ovary 1.5–2 mm long, longitudinally ribbed (when dried), densely covered with short erect hairs; placentation unknown. Fruits ovoid, 10–13 × 8–10 mm, strongly ribbed longitudinally (when dried), densely covered with short erect hairs; fruit wall well-developed, with multi-layered anastomosing network of sclerified vascular bundles; pyrenes hemi-ovoid, ca 6.5 × 5 mm, crustaceous, with rounded base, acuminate tip, small adaxial opening in upper ⅓ rd and faint longitudinal central ridge running from the apex to the top of the adaxial opening and continuing into a longitudinal depression below it; pyrene opening along this longitudinal ridge and depression. Seeds 4–8 per fruit, 3–5 × 2–3.5 mm.
Distribution
Restricted to the Central Highlands. Present in: Ankazobe and Renivohitra Districts, Analamanga Region, and Antanifotsy District, Vakinankaratra Region (Antananarivo Province); Ambatofinandrahana and Ambositra Districts, Amoron’i Mania Region (Fianarantsoa Province) (Fig. 23A).
Habitat and phenology
High plateau forest, gallery forest; elev. 1200–1700 m. Flowers: November–January; Fruits: February– November.
Vernacular name
Tsitola (coll. ignot. 5218-SF).
Provisional IUCN assessment
Endangered: EN B2ab(iii). This assessment is based on 15 herbarium collections with detailed locality data, collected between 1945 and 2018. A 16 th specimen was collected in the arboretum of the Parc botanique et zoologique de Tsimbazaza in 1975 (Croat 28780). No information was found on whether this tree had been planted or whether it occurred naturally in the arboretum. During searches in 2010, this tree was not found (Franck Rakotonasolo: pers. com.). As a result, this location is not taken into account for this assessment. The EOO of P. capitulifera sp. nov. is estimated to be 19 843 km 2, which complies with the Vulnerable category under criterion B1. The AOO is 36 km 2, which complies with the Endangered category under criterion B2. The species occurs in 5 locations, which is the upper limit for the Endangered category under subcriterion ‘a’ of criterion B2. Paracephaelis capitulifera sp. nov. is restricted to the Central Highlands, which are densely populated and house several large cities. Human impact is high, consisting of subsistence agriculture (rice, manioc, sweet potatoes, …) and extensive cattle grazing, for which yearly burning of the grasslands is affected (McConnell et al. 2015). Throughout the Central Highlands, most forest cover has been destroyed (Gade 1996), with only small patches remaining. Paracephaelis capitulifera sp. nov. occurs in Ambohitantely Special Reserve and Itremo New Protected Area, both of which are threatened by bushfires and cattle grazing. Also, logging for construction wood, firewood and, wood for charcoal production, collection of plants for medicinal, subsistence or ornamental use, and hunting take place (Nicoll & Langrand 1989; Langrand 2003; La Maison de Madagascar 2020). Additional threats to the natural vegetation in Itremo are artisanal mining and invasive species (Pinus L.; La Maison de Madagascar 2020). Because of the above-mentioned facts, a reduction in the extent and quality of the habitat of P. capitulifera sp. nov. is inferred. This threat, in combination with the low AOO and the low number of locations, qualifies P. capitulifera sp. nov. as Endangered.
Notes
1. One specimen with mature flowers was seen online (P). In coll. ignot. 1035-SF, the corolla tube is ca 13 mm long and the corolla lobes ca 5 mm long. The flowers could not be studied.
2. Prior to the synonymization of Homollliella with Paracephaelis (De Block et al. 2015), herbarium specimens were annotated by the author as “ Homolliella capitulifera ”, a name which was never published.
description: Published as part of Block, Petra De, 2022, Monograph of the western Indian Ocean genus Paracephaelis (Rubiaceae - Pavetteae), with description of thirteen new species, pp. 1-99 in European Journal of Taxonomy 801 on pages 27-30, DOI: 10.5852/ejt.2022.801.1685, http://zenodo.org/record/6358810