![Thumbnail: [Volume 88, 1960-61 page 401]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_03_0444_0401_ac_02.gif)
List of the Flora of Oeno Atoll, Tuamotu Archipelago, South-Central Pacific Ocean
[Received by the Editor, February 15, 1960.]
Abstract
A brief description of Oeno Atoll is followed by a list of the plants found growing there.
Oeno Atoll is an uninhabited coral island, south of Mangareva, and about 65 miles north-west of Pitcairn Island, and almost at the south end of the Tuamotu Archipelago. One of us (H. St. J.) spent June 23, 1934, exploring it with his assistant, F. R. Fosberg. This was while serving as botanist on the Mangarevan Expedition of the B. P. Bishop Museum.
The atoll is about 2½ miles in diameter, its bounding coral reef enclosing a lagoon. Near the northern edge of the lagoon are two small, sandy islets a few feet above water. The principal islet lies near the centre of the lagoon. Originally this supported a vegetation with shrub thickets and trees. Later, part of the islet was exploited, and in 1902 planted to coconuts. This plantation was infrequently visited by people from the Gambier Is. Other parts of the islet were undisturbed. It was the impression of the collectors that the flora was well preserved, and that few, if any, of the native species were overlooked.
The earlier collection by E. H. Quayle and Curtis of the Whitney Expedition in 1921–23, contained no additional species. Nor did the collection on October 16, 1956, by G. R. Williams, except for a single adventive species of Brassica. His collections are preserved in the herbarium of the Dominion Museum, Wellington. The other collections are in the B. P. Bishop Museum.
The known flora consists of 1 alga, 2 ferns, 4 Monocotyledons, and 11 Dicotyledons. Though the floras of most Pacific atolls are monotonous, this one has features of interest. It has an endemic species of Pandanus, an endemic variety of Bidens, and is the type locality of a forma of Achyranthes
List of the Flora
Algae, Cyanophyceae
Tolypothrix byssoidea (Hass.) Kirchn.
St. John & Fosberg 15,201. Occurring as globules on sand in moist hollows.
Pteridophyta
Aspleniaceae
Asplenium nidus L.
Quayle 409; St. John & Fosberg 15,184; Williams 3,024. On the ground and on fallen logs. See Brown, Bishop Mus., Bul. 89: 58, 1931; Copeland, Bishop Mus., Occ. Pap. 14: 64, 1938.
![Thumbnail: [Volume 88, 1960-61 page 402]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_03_0445_0402_ac_02.gif)
Polypodiaceae
Phymatodes scolopendria (Burm.) Ching.
Quayle 400; St. John & Fosberg 15,189. On coral sand under trees. See Brown, Bishop Mus., Bul. 89: 97–98, 1931; Copeland, Bishop Mus., Occ. Pap. 14: 74, 1938.
Spermatophyta
Pandanaceae
Pandanus feruliferus St. John, sp. nov.
St. John & Fosberg 15,197. This is being described separately, in St. John's revision of Pandanus.
Gramineae
Lepturus repens (Forst. f.) R. Br. var. repens
St. John & Fosberg 15,190; Williams 3,022. Tufted on coral sand near beach.
Palmae
Cocos nucifera L. Planted for copra production. Reported by Fosberg, 6th Pacif. Sci. Congr., Proc. 4: 503, 1940.
Amaryllidaceae
Crinum sp. (probably asiaticum).
St. John & Fosberg 15,193. One sterile specimen, planted beside a shanty.
Nyctaginaceae
Boerhavia diffusa L. var. tetrandra (Forst. f.) Heimerl.
St. John & Fosberg 15,191; 15,196; 15,203; Williams 3,006; 3,025. Repent on coral sand. See Heimerl, Bishop Mus., Occ. Pap. 13: 30, 1937.
Pisonia grandis R. Br.
Quayle & Curtis 407; St. John & Fosberg 15,186. Common as a shrub up to 2 m tall in Messerschmidia woods; only one arborescent specimen seen, this 9 m tall, 15 cm in diameter. See Heimerl, Bishop Mus., Occ. Pap. 13: 37, 1937.
Amaranthaceae
Achyranthes velutina H. & A. forma rosea Suessenguth.
Quayle & Curtis 408; St. John & Fosberg 15,199, Williams 3,028. Decumbent on coral sand, in forest openings. Suessenguth, Bishop Mus., Occ. Pap. 12: 5, 1936, listed four collections for his new forma, without designating a type. The specimen, St. John & Fosberg 15,199 (BISH) is here chosen as lectotype.
Lauraceae
Cassytha filiformis L.
St. John & Fosberg 15,187; Williams 3,026; 3,028. A parasite, trailing on ground and bushes.
Cruciferae
Brassica juncea (L.) Coss.
Williams 3,027.
Lepidium bidentatum Montin, (L. bidentoides F. Br.)
Quayle & Curtis 406A; 406B; St. John & Fosberg 15,188; Williams 3,026; 3,027. On sand flats and sandy openings. See Brown, Bishop Mus., Spec. Publ. 11: 26, 1926; and Bul. 130: 94, 1935.
![Thumbnail: [Volume 88, 1960-61 page 403]](/journals/rsnz/images/rsnz_88/thumbnails/rsnz_88_03_0446_0403_ac_02.gif)
Simaroubaceae
Suriana maritima L.
St. John & Fosberg 15,202; Williams 3,091. On coral gravel near beach.
Boraginaceae
Messerschmidia argentea (L. f.) Johnston.
Quayle & Curtis 404; St. John & Fosberg 15,194; Williams 2,023. The dominant tree, forming forests on coral sands; the largest one 10 m tall, 1.5 m in diameter.
Solanaceae
Solanum tuamotuense St. John.
St. John & Fosberg 15,185; Williams 3,021. This species is described in Journ. Jap. Bot., 34: 337–340, 1959.
Rubiaceae
Hedyotis romanzoffiensis (C. & S.) Fosberg.
Quayle & Curtis 403, St. John & Fosberg 15,192; 15,198; 15,200; Williams 3,029. Shrub, on coral shingle. See Bishop Mus., Occ. Pap. 13: 248, 1937.
Compositae
Bidens hendersonensis Sherff var. oenoensis Sherff.
St. John & Fosberg 15,183 (holotype). Decumbent or erect, under Messerschmidia trees. See Sherff, Bishop Mus., Occ. Pap. 12 (19): 7, pl. 4, 1937.
H. St. John,
Bernice P. Bishop Museum, Honolulu, Hawan.
W. R. Philipson,
University of Canterbury, P. O. Box 1471, Christchurch, N.Z.