Flora of St Helena
Encyclopedia
The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing the survival of the flora. In phytogeography
, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom
.
include many notable "insular arborescent Asteraceae
", that is, members of the daisy family
which have evolved a shrubby or tree-like habit on islands. Other notable endemics include the closely related St Helena redwood (Trochetiopsis erythroxylon
) and St Helena dwarf ebony (Trochetiopsis ebenus
). These are unrelated to the redwood trees of California or to the ebony trees of commerce
, being instead in the Mallow family (Malvaceae
).
) and other trees, now largely destroyed. The "Crown wastes" or coastal zones were formerly covered with native scrub, of which a major component was probably St Helena dwarf ebony (Trochetiopsis ebenus
and St Helena tree ebony Trochetiopsis melanoxylon
).
Dicotyledons
Pteridophytes (Ferns and fern-allies)
Phytogeography
Phytogeography , also called geobotany, is the branch of biogeography that is concerned with the geographic distribution of plant species...
, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom
Paleotropical Kingdom
The Paleotropical Kingdom is a floristic kingdom comprising tropical areas of Africa, Asia and Oceania , as proposed by Ronald Good and Armen Takhtajan. Its flora is characterized by about 40 endemic plant families, e.g. Nepenthaceae, Musaceae, Pandanaceae, Flagellariaceae...
.
Endemic and introduced flora
The endemic plants of Saint HelenaSaint Helena
Saint Helena , named after St Helena of Constantinople, is an island of volcanic origin in the South Atlantic Ocean. It is part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha which also includes Ascension Island and the islands of Tristan da Cunha...
include many notable "insular arborescent Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
", that is, members of the daisy family
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...
which have evolved a shrubby or tree-like habit on islands. Other notable endemics include the closely related St Helena redwood (Trochetiopsis erythroxylon
Trochetiopsis erythroxylon
Although the Saint Helena Redwood is now extinct in the wild, it was formerly abundant enough in the upland parts of the island of Saint Helena for early settlers in the 17th century to use the timber to make their homes....
) and St Helena dwarf ebony (Trochetiopsis ebenus
Trochetiopsis ebenus
Saint Helena ebony is a species of flowering plant that is endemic to the island of Saint Helena in the southern Atlantic Ocean. It is not related to the ebony of commerce , but is instead a member of the mallow family, Malvaceae...
). These are unrelated to the redwood trees of California or to the ebony trees of commerce
Diospyros
Diospyros is a genus of about 450–500 species of deciduous and evergreen trees. The majority are native to the tropics, with only a few species extending into temperate regions. They are commonly known as ebony or persimmon trees...
, being instead in the Mallow family (Malvaceae
Malvaceae
Malvaceae, or the mallow family, is a family of flowering plants containing over 200 genera with close to 2,300 species. Judd & al. Well known members of this family include okra, jute and cacao...
).
Vegetation
Today there are three major vegetation zones: the tree-fern thicket of the highest parts of the central ridge; the pastures of middle elevations and the dry, eroded "crown wastes" of lower elevations. Of these only the tree-fern thicket is a natural vegetation type. The middle elevations were formerly covered with native woodland of gumwoods (CommidendrumCommidendrum
Commidendrum is a genus of four species of trees and shrubs in the family Asteraceae endemic to the island of Saint Helena in the South Atlantic Ocean. The vernacular name is gumwood or scrubwood.Species...
) and other trees, now largely destroyed. The "Crown wastes" or coastal zones were formerly covered with native scrub, of which a major component was probably St Helena dwarf ebony (Trochetiopsis ebenus
Trochetiopsis ebenus
Saint Helena ebony is a species of flowering plant that is endemic to the island of Saint Helena in the southern Atlantic Ocean. It is not related to the ebony of commerce , but is instead a member of the mallow family, Malvaceae...
and St Helena tree ebony Trochetiopsis melanoxylon
Trochetiopsis melanoxylon
The Dwarf Ebony of the island of Saint Helena is related to Trochetiopsis ebenus but is now extinct...
).
Human impact and conservation
The destruction of the native vegetation began soon after the discovery of the island by the Portuguese in 1502, with the introduction of goats. As there were no native herbivorous mammals, the flora was unadapted to such threats. Later with the establishment of permanent settlement on the island by the English East India Company in 1659, many introduced plants became established which created new vegetation types. Furthermore the native trees were subject to catastrophic cutting for such purposes as housebuilding and to fuel stills for the distillation of arrack. As a result of this legacy many endemic plant species are extinct or critically endangered.Endemic vascular plants of St Helena
Monocotyledons- Bulbostylis lichtensteiniana (Kunth) C.B. Clarke
- Bulbostylis neglectaBulbostylis neglectaBulbostylis neglecta, neglected tuft sedge locally, is an endemic member of the Cyperaceae of Saint Helena in the South Atlantic. It was first collected by William John Burchell in 1806...
(Hemsl.) C.B. Clarke - Carex dianae Steud.
- Carex praealta Boott
- Eragrostis saxatilis Hemsl.
Dicotyledons
- Acalypha rubrinervisAcalypha rubrinervisAcalypha rubrinervis is an extinct plant in the spurge family , from the island of Saint Helena in the South Atlantic Ocean. It was called string tree on account of the thin pendulous inflorescences which resembled red strings...
Cronk - Chenopodium helenense Aellen
- Commidendrum robustumCommidendrum robustumThe Saint Helena gumwood , although now comparatively rare, was once one of the most abundant trees of mid-elevations of the island of Saint Helena in the South Atlantic Ocean. A small tree to 7-8 m, it was cut extensively for fuel in the early years of settlement of the island by the English East...
(Roxb.) DC. ssp. robustum - Commidendrum robustumCommidendrum robustumThe Saint Helena gumwood , although now comparatively rare, was once one of the most abundant trees of mid-elevations of the island of Saint Helena in the South Atlantic Ocean. A small tree to 7-8 m, it was cut extensively for fuel in the early years of settlement of the island by the English East...
(Roxb.) DC. ssp. gummiferum (Roxb.) Cronk - Commidendrum rotundifoliumCommidendrum rotundifoliumThe Bastard Gumwood is a species of tree endemic to the island of Saint Helena. It was thought to be extinct, but one last tree was discovered in Horse Pasture in 1982. This tree, long believed to be the last, was destroyed in 1986 by a gale. Fortunately seedlings were grown from this tree before...
(Roxb.) DC. - Commidendrum rugosumCommidendrum rugosumThe Scrubwood is a species of flowering plant in the Asteraceae family.It is found only in Saint Helena.Its natural habitats are subtropical or tropical dry shrubland, rocky areas, and rocky shores....
(Aiton) DC. - Commidendrum spuriumCommidendrum spuriumThe False Gumwood is a species of flowering plant in the Asteraceae family.It is found only in Saint Helena.Its natural habitats are subtropical or tropical moist lowland forests, rocky areas, and rocky shores....
(G. Forst.) DC. - Euphorbia heleniana Thell. & Stapf
- Frankenia portulacifoliaFrankenia portulacifoliaFrankenia portulacifolia is a species of plant in the Frankeniaceae family. It is endemic to Saint Helena. Its natural habitats are subtropical or tropical dry forests, rocky areas, and rocky shores.-Source:* Cairns-Wicks, R 2003. . Downloaded on 21 August 2007....
(Roxb.) Spreng. - Heliotropium pannifoliumHeliotropium pannifoliumThe Saint Helena Heliotrope is now extinct but was formerly a hairy-leaved small shrub up to 1 m in height. it was only seen once, by the explorer W. Burchell in Broad Gut, Saint Helena and has never been seen again...
Burch. ex Hemsl. - Hydrodea cryptantha (Hook.f.) N.E.Br.
- Hypertelis acida (Hook.f.) K. Müll.
- Lachanodes arboreaLachanodes arboreaShe Cabbage Tree is a small tree in the Asteraceae family. It is an endangered endemic of the island of Saint Helena in the South Atlantic Ocean, and one of several types of cabbage tree on the island.-References:...
(Roxb.) B. Nord. - Melanodendron integrifolium (Roxb.) DC.
- Mellissia begoniifolia (Roxb.) Hook.f.
- Nesiota elliptica (Roxb.) Hook.f.
- Nesohedyotis arborea (Roxb.) Bremek.
- Osteospermum sanctae-helenae Norl.
- Pelargonium cotyledonisPelargonium cotyledonisPelargonium cotyledonis is an endemic of the island of Saint Helena in the South Atlantic Ocean. It is a white flowered, deciduous succulent plant, and is considered endangered.-External links:*...
(L.) L'Hér. - Petrobium arboreum (J.R. & G. Forst.) R. Br.
- Phylica polifoliaPhylica polifoliaPhylica polifolia is a species of plant in the Rhamnaceae family. It is endemic to Saint Helena. Its natural habitats are rocky areas and rocky shores.-Source:...
(Vahl) Pillans - Pladaroxylon leucadendronPladaroxylon leucadendronThe He Cabbage Tree is one of three cabbage tree species from the island of Saint Helena in the South Atlantic Ocean, where it is endangered. It is a small tree in the Asteraceae family. It is called the "He Cabbage Tree" as the young leaves are hairy, in contrast to the hairless leaves of the She...
( G. Forst.) Hook.f. - Plantago robusta Roxb.
- Sium bracteatumSium bracteatumSium bracteatum is a species of plant in the Apiaceae family. It is endemic to Saint Helena. Its natural habitats are subtropical or tropical moist lowland forests, heavily degraded former forest, and introduced vegetation. It is threatened by habitat loss.-Source:* Cairns-Wicks, R. 2003. . ...
(Roxb.) Cronk - Sium burchelliiSium burchelliiSium burchellii or the Dwarf Jellico is a species of flowering plant in the Apiaceae family.It is endemic to the island of Saint Helena.Its natural habitats are subtropical or tropical moist lowland forests and rocky areas....
(Hook.f.) Hemsl. - Suaeda fruticosa Forssk. ex J.F. Gmel.
- Trimeris scaevolifoliaTrimeris scaevolifoliaTrimeris scaevolifolia is the sole member of the endemic genus Trimeris from the island of Saint Helena.-References:* Cronk, Q.C.B. The endemic Flora of St Helena. Anthony Nelson Ltd, Oswestry....
(Roxb.) Mabb. - Trochetiopsis ebenusTrochetiopsis ebenusSaint Helena ebony is a species of flowering plant that is endemic to the island of Saint Helena in the southern Atlantic Ocean. It is not related to the ebony of commerce , but is instead a member of the mallow family, Malvaceae...
Cronk - Trochetiopsis erythroxylonTrochetiopsis erythroxylonAlthough the Saint Helena Redwood is now extinct in the wild, it was formerly abundant enough in the upland parts of the island of Saint Helena for early settlers in the 17th century to use the timber to make their homes....
(G. Forst.) Marais - Trochetiopsis melanoxylonTrochetiopsis melanoxylonThe Dwarf Ebony of the island of Saint Helena is related to Trochetiopsis ebenus but is now extinct...
(Sol. ex Sims) Marais - Trochetiopsis x benjaminii Cronk
- Wahlenbergia angustifoliaWahlenbergia angustifoliaWahlenbergia angustifolia is a species of plant in the Campanulaceae family. It is endemic to Saint Helena. Its natural habitat is rocky areas. It is endangered because of habitat loss.-References:...
(Roxb.) A.DC. - Wahlenbergia burchellii A.DC. in DC.
- Wahlenbergia linifoliaWahlenbergia linifoliaWahlenbergia linifolia is a species of plant in the Campanulaceae family. It is endemic to Saint Helena. Its natural habitat is rocky areas. It is threatened by habitat loss.-Source:...
(Roxb.) A.DC. - Wahlenbergia roxburghiiWahlenbergia roxburghiiWahlenbergia roxburghii is an extinct member of a group of four species of Wahlenbergia once known from the island of Saint Helena, in the South Atlantic Ocean...
A.DC.
Pteridophytes (Ferns and fern-allies)
- Asplenium compressum Sw.
- Asplenium platybasis Kunze ex Mett.
- Ceterach haughtoni (Hook.) Cronk
- Dicksonia arborescensDicksonia arborescensThe Saint Helena Tree Fern is a characteristic plant of the "tree fern thicket" vegetation of the highest parts of the central ridge of the island of Saint Helena....
L'Hér. - Diplazium filamentosum (Roxb.) Cronk
- Dryopteris cognata (C. Presl) Kuntze
- Dryopteris napoleonis (Bory) Kuntze
- Elaphoglossum dimorphum (Hook. & Grev.) Moore
- Elaphoglossum nervosum (Bory) H.Christ
- Grammitis ebenina (Maxon) Tardieu
- Hymenophyllum capillaceum Roxb.
- Lycopodium axillare Roxb.
- Microstaphyla furcata (L.f.) Fée
- Ophioglossum polyphyllum A. Braun
- Pseudophegopteris dianae (Hook.) Holttum
- Pteris paleacea Roxb.
Endemic genera
- CommidendrumCommidendrumCommidendrum is a genus of four species of trees and shrubs in the family Asteraceae endemic to the island of Saint Helena in the South Atlantic Ocean. The vernacular name is gumwood or scrubwood.Species...
- LachanodesLachanodesLachanodes is a genus of the tribe Senecioneae and the family Asteraceae....
- MelanodendronMelanodendronMelanodendron integrifolium is one of the endemic trees in the Asteraceae family from the island of Saint Helena...
- MellissiaMellissiaMellissia is a genus in the family Solanaceae with a single species, Mellissia begoniifolia , that is endemic to the island of Saint Helena...
- Nesiota
- NesohedyotisNesohedyotisNesohedyotis is an endemic genus of flowering plants from the island of Saint Helena in the South Atlantic Ocean. It in the family Rubiaceae ....
- PetrobiumPetrobiumPetrobium is a monotypic genus in the family Asteraceae endemic to the island of Saint Helena in the South Atlantic Ocean. The vernacular name is Whitewood....
- PladaroxylonPladaroxylonPladaroxylon is a genus of the tribe Senecioneae and the family Asteraceae....
- TrimerisTrimerisTrimeris is a genus of the plant family Campanulaceae endemic to the island of St Helena in the South Atlantic Ocean.SpeciesThere is a single species*Trimeris scaevolifolia Mabb. - St Helena lobelia, milkwood-External links :*...
- TrochetiopsisTrochetiopsisThe flowering plant genus Trochetiopsis consists of two extant and one extinct species endemic to the island of Saint Helena...
See also
- Wildlife of Saint Helena, Ascension and Tristan da Cunha
- List of extinct plants (includes several from Saint Helena)