Skip to main content
This species is accepted, and its native range is São Tomé, Príncipe.

[KBu]

Mesterházy, A. & Browning, J. 2014. A rare enigmatic sedge rediscovered: Principina grandis (Cyperaceae) newly recorded from São Tomé. Kew Bulletin 69: 9532. DOI https://doi.org/10.1007/s12225-014-9532-y

Conservation
Currently Principina grandis is known from only two localities, one on Príncipe and the other on São Tomé. Because this species formerly was known only from the type specimen, P. grandis has not been included in the latest IUCN Red List (IUCN Red List of Threatened Species 2013). This species seems to be rare, but both of the localities are in dense primary forest and difficult to reach. Three trachytes occur on São Tomé and five on Príncipe (Caldeira et al. 2004). Pico Maria Fernandes is included in Obo National Park, while Pico Papagaio is a part of Zona Ecologica. These are far from settlements and are not threatened by human activities. More research is needed to study the flora of trachytes, but this is difficult without special climbing equipment. It is likely that P. grandis is more widespread in these particular island habitats and awaits further investigation and collection. For this reason the conservation status of the species should, at present, be considered as Least Concern (LC) (IUCN Red List Categories and Criteria 2001).
Distribution
The type collection was collected on Príncipe island (Pico Papagaio) and the new record from São Tomé (Pico Maria Fernandes). Both islands are situated north of the equator in the Gulf of Guinea, approximately 140 km apart. Principina grandis is endemic to São Tomé and Príncipe.
Ecology
Neither the original diagnosis (Uittien 1935), nor Exell’s monograph (Exell 1944) gave any information on the habitat of this species, apart from ‘summit of Pico Papagaio’. The recent specimen was collected on Pico Maria Fernandes. This mountain is composed of a type of igneous volcanic rock, which originated in volcanic vents, that is known as a trachyte. Having high (60 – 65%) silica content, trachytes are more resistant to erosion and are preserved in pillar-like form. Their slopes are quite steep, with the summit more or less flat and covered by dense forest. Principina grandis was collected on the slopes of Pico Maria Fernandes, where the slope angle was almost 90°. The habitat was an open rock face and soil was found only in the cracks. The plant grew on a shaded cliff. The understorey was poorly developed and there were only very small, “shrub-like” trees. The vegetation surrounding the mountain was dense rainforest and the forest became more open only on the very steep cliffs. P. grandis was found only the SW part of Pico Maria Fernandes in 428 m altitude. Other Cyperaceae were not collected in this habitat, but on another part of the mountain SclerialagoensisBoeck. was found. The type specimen of Principina may have been collected from a similar habitat, because Pico Papagaio is also a trachyte mount. Trachyte mounts are not known from other islands in Gulf of Guinea.
Morphology Branches
Branches, 1.5 cm long max, bearing 1 – 3 spikes
Morphology Culms
Culm erect, central 1.82 × 0.25 cm, tall, trigonous, smooth, scabrous below the inflorescence
Morphology General Habit
Robust perennial with 1 cm thick rhizome
Morphology Leaves
Cauline leaf 1, three nerved, 50 × 0.8 cm Basal leaves numerous (15) 0.7 – 0.5 × 110 cm, linear, 3-nerved, nerves minutely scabrous below, apex gradually acute
Morphology Reproductive morphology Flowers Androecium Stamens Filaments
Filaments 3, 2 lateral, 3rd abaxial side of ovary
Morphology Reproductive morphology Flowers Florets
Floret bisexual-Anthers not seen
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary slightly developed and enlarged, with marginal narrowing at base (stipitate) and short apex The ovary had closely placed discoid dark brown to black patches Length in one spicoid 1 mm
Morphology Reproductive morphology Flowers Gynoecium Style
Style 1.35 – 1.5 mm long, branches 3, 1.4 – 1.5 mm long, 0.125 mm wide, and dark greyish purple/brown in colour, very rough surface, papillae not obvious
Morphology Reproductive morphology Fruits
Nutlet not seen.
Morphology Reproductive morphology Inflorescences
Length of spike branch 6 mm; scabrid, channelled, width 0.5 mm below spike Spicoids 3 × ± 0.5 mm, longer than bracts; floral bracts 2, united, bladder-like, in lower bracts with well defined marginal spines (prickles or teeth) (Fig. 1C, D) less obvious in upper; abaxially convex, adaxially concave Spikes 5.5 – 5.8 × 3.3 – 3.5 mm, many-flowered Inflorescence corymbose-paniculate, whorled, narrowly oblong 12.5 cm, the internodes trigonous, scabrid the first 8.5 cm, the second 2 cm, the third 1 cm. The number of branches of the whorl from below 1-8-7-5.
Morphology Reproductive morphology Inflorescences Bracts
Spicoid bract (glume) 2.5 × 1.0 – 1.25 mm, light brown and streaked with darker brown, oblong, obtuse, almost glabrous, few cilia or spine-like teeth, no obvious mid-vein, rounded at apex, split and frayed on all bracts in material examined Lowermost bract 22 × 0.9 cm, 3-nerved
Note
The parameters of this collection from São Tomé match the type specimen except for the height and overall inflorescence dimensions. The plant was collected in May, at early flowering stage, while the type material had been collected from Príncipe in December, and many of the spikes had matured and fallen. Uittien noted for the type that there was only one nutlet present, describing it as subglobose, base acute, apex acuminate, 3-keeled, 2.5 mm long, with convex sides; generally with three longidtudinal sinuous ridges, glabrous, yellowish.

During the eight decades that have elapsed since the original and only collection of Principina grandis was made by Exell, various workers have tried to accommodate this enigmatic plant in either the genus Hypolytum or Mapania. Criteria used often singly it may seem, have been based on inflorescence form, number and appearance of floral bracts, number of style branches and conformation of nutlet.

Placement in the genus Mapania may be favoured by the possession as in sect. Pycnocephala of three floral bracts and three style branches, but the latter is not the case in African species. The inflorescence form in this section is globose and not corymbose paniculate.

With the genus Hypolytrum there is perhaps more conformity in inflorescence form and floral bract number, but not in number of style branches. This character is however very unreliable not only in the tribe Mapanioideae, in which Mapania and Hypolytrum are included, but in other genera of the tribe Cyperoideae.

There is little doubt now that with this second authenticated collection, Principina grandis stands apart with the combination of characters given by Uittien and here confirmed. The whorled arrangement of the corymbose paniculate inflorescence as seen in Fig. 1B, the united floral bracts giving a ‘bladder-like’ structure, Fig. 1B – F, and the three wide style branches are distinctive. The similar habitat in which the collections were made, namely trachyte mountains in dense rain forest, should also be noted. The genus Principina is an accepted genus in Govaerts et al. (2007) but to clarify its status, molecular work is much needed.

Type
Type: Príncipe, Exell 703 (holotype BM).

Native to:

Gulf of Guinea Is.

Principina grandis Uittien appears in other Kew resources:

First published in Recueil Trav. Bot. Néerl. 32: 282 (1935)

Accepted by

  • Govaerts, R. & Simpson, D.A. (2007). World Checklist of Cyperaceae. Sedges: 1-765. The Board of Trustees of the Royal Botanic Gardens, Kew.
  • Govaerts, R. (2004). World Checklist of Monocotyledons Database in ACCESS: 1-54382. The Board of Trustees of the Royal Botanic Gardens, Kew.

Literature

Kew Bulletin

  • Caldeira, R., Munha, J. M., Madeira, J., Afonso, R., Nascimento, E. & Mata, J. (2004). Geological map of São Tomé Islands, Gulf of Guinea: A management tool towards sustainable development. — 20th Colloquium African Geology, Abstr. Vol. 103.
  • Exell, A. W. (1944). Catalogue of the Vascular Plants of São Tomé (with Príncipe and Annobon). British Museum, London.
  • Figueiredo, E., Paiva, J., Stévart, T., Oliveira, F. & Smith, G. F. (2011). Annotated catalogue of the flowering plants of São Tomé and Príncipe. Bothalia 41 (1): 41 – 82.CrossRefGoogle Scholar
  • Goetghebeur, P. (1998). Cyperaceae. In: K. Kubitzki (ed.), The Families and Genera of Vascular Plants IV. Flowering plants — monocotyledons, pp. 141 – 190. Springer-Verlag, Berlin.
  • Govaerts, R., Simpson, D. A., Bruhl, J. J., Egorova, T., Goetghebeur, P. & Wilson, K. L. (2007). World Checklist of Cyperaceae. Sedges. Royal Botanic Gardens, Kew.
  • IUCN (2001). Red List Categories and Criteria, Version 3. 1. IUCN, Gland and Cambridge. http://www.iucnredlist.org/
  • IUCN (2013). IUCN Red List of Threatened Species. Version 2013.2. http:/www.iucnredlist.org/ Downloaded on 3 May 2014Google Scholar
  • Koyama, T. (1961). Classification of the family Cyperaceae 1. J. Fac. Sci. Univ. Tokyo, Sect. 3, Bot. 8: 37 – 148.
  • Koyama, T. (1969). Delimitation and classification of the Cyperaceae-Mapanioideae. In: J. E. Gunkel (ed.), Current topics in plant science, pp. 201 – 228. Academic Press, New York.
  • Uittien, H. (1935). Principina, genus novum CyperacearumAfricanum. Recueil Trav. Bot. Néerl. 32: 282 – 285.

Kew Backbone Distributions

  • Figueiredo, E., Paiva, J., Stévart, T., Oliveira, F. & Smith, G.F. (2011). Annotated catalogue of the flowering plants of São Tomé and Príncipe Bothalia 41: 41-82.

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Bulletin
Kew Bulletin
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0