Palaquium galactoxylum

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Pencil cedar
Palaquium galactoxylum SF20305 01.jpg
Fruits and seeds

Least Concern (IUCN 3.1)[1]
Least Concern (NCA)[2]
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Ericales
Family: Sapotaceae
Genus: Palaquium
Species:
P. galactoxylum
Binomial name
Palaquium galactoxylum
Synonyms[3]
  • Bassia galactoxyla F.Muell.
  • Galactoxylon pierrei Baill.
  • Palaquium salomonense C.T.White
  • Sersalisia galactoxylon (F.Muell.) F.Muell. ex Benth.

Palaquium galactoxylum is a species of flowering plant in the family Sapotaceae, endemic to rainforests of northern Australia and New Guinea.

Description[]

Palaquium galactoxylum is a rainforest tree growing up to 40 metres (130 ft) high, thus becoming an emegent within the forest ecosystem. It has a very straight cylindrical trunk marked with conspicuous vertical lines of lenticels, which usually reaches a width of 1 m (3 ft 3 in) diameter,[4] but it may reach up to 2 m (6.6 ft),[5] It has buttress roots up to 2 m (6.6 ft) high.[6][7] The trunk, branches and leaves all exude a milky sap when cut.[4][7] It is semi-deciduous, dropping its leaves for a short period around October.[4][6]

The leaf-bearing twigs are scarred and rough looking;[8] young twigs and new shoots are clothed in fine brown hairs.[4] Leaves are glabrous and clustered towards the end of the twigs.[7] They are rounded at the tip and cuneate at the base, and measure up to 13 cm (5.1 in) long by 5 cm (2.0 in) wide. The short petiole is about 13 mm (0.51 in) long.[4][8]

The inflorescences are axillary, produced on the leaf-bearing twigs below the leaves.[7] The fruits are an ellipsoid (i.e. like a rugby ball), creamy-white drupe about 40 mm (1.6 in) long by 20 mm (0.79 in) wide.[4] They contain one, sometimes two, seeds measuring up to 25 by 20 mm (1.0 by 0.8 in).[4][7][8]

Taxonomy[]

Flowers (J.L.Dowe)

The taxonomy of this species has a somewhat convoluted history with a number of authors describing it and assigning various names. The name currently accepted by most authorities is Palaquium galactoxylum (F.Muell.) H.J.Lam, with combinations by Henri Ernest Baillon, Cyril Tenison White, Pieter van Royen, George Bentham, and even a second description published by Ferdinand von Mueller all being discarded.[3][9][10][11]

In Australian botany, the species' accepted name is Palaquium galactoxylon.[2][4][12]

Subspecies[]

As of 6 September 2021 the subspecies Palaquium galactoxylum var salmonense (C.T.White) P.Royen is accepted by the Papua New Guinea National Herbarium, the Global Biodiversity Information Facility, World Flora Online and Catalogue of Life,[7][13][14][15] but not by Plants of the World Online which considers the taxon to be a synonym.[16]

Etymology[]

The genus name Palaquium comes from the Philippine word palakihun meaning "to let grow". The species epithet is from Ancient Greek galacto- (milky), and -xylon (wood, timber), referring to the copious white sap the plant produces.[17]

Distribution and habitat[]

Palaquium galactoxylum grows in tropical low-altitude rainforests of New Guinea (including the Bismarck Archipelago), the Solomon Islands, and Queensland, at elevations to around 300 m (1,000 ft).[1][4]

Ecology[]

Fruits of this species are eaten by cassowaries and fruit doves, including the Torresian imperial pigeon.[4][17]

Conservation[]

P. galactoxylum has no immediate threats, being relatively common and having a broad distribution. It is therefore listed as least concern by both the IUCN and the Queensland Department of Environment and Science.[1][2]

Uses[]

This tree produces a useful hardwood timber which is sold as "Pencil Cedar".[4][6]

References[]

  1. ^ a b c IUCN SSC Global Tree Specialist Group & Botanic Gardens Conservation International (BGCI) (2019). "Palaquium galactoxylum". IUCN Red List of Threatened Species. 2019: e.T129333512A154753279. doi:10.2305/IUCN.UK.2019-3.RLTS.T129333512A154753279.en. Retrieved 5 September 2021.CS1 maint: multiple names: authors list (link)
  2. ^ a b c "Species profile—Palaquium galactoxylon". Queensland Department of Environment and Science. Queensland Government. 2019. Retrieved 5 September 2021.
  3. ^ a b c "Palaquium galactoxylum var. salmonense (F.Muell.) H.J.Lam". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 September 2021.
  4. ^ a b c d e f g h i j k F.A.Zich; B.P.M.Hyland; T.Whiffen; R.A.Kerrigan (2020). "Palaquium galactoxylon". Australian Tropical Rainforest Plants Edition 8 (RFK8). Centre for Australian National Biodiversity Research (CANBR), Australian Government. Retrieved 5 September 2021.
  5. ^ "Occurrence record: QRS 103276.1". Australasian Virtual Herbarium. Council of Heads of Australasian Herbaria (CHAH). Retrieved 5 September 2021.
  6. ^ a b c Ken Fern. "Palaquium galactoxylum". Useful Tropical Plants. Retrieved 14 July 2020.
  7. ^ a b c d e f Conn, B.J.; Banka, R.; Lee, L.L. "PNGTreesKey – Palaquium galactoxylum (F.Muell.) H.J.Lam var. salomonense (C.T.White) P.Royen". Plants of Papua New Guinea. Retrieved 6 September 2021.
  8. ^ a b c Mueller, Ferdinand von (1868). Fragmenta Phytographiae Australiae. 6. p. 27. Retrieved 6 September 2021.
  9. ^ "Palaquium galactoxylon (C.T.White) P.Royen". Global Biodiversity Information Facility. Retrieved 6 September 2021.
  10. ^ "Palaquium galactoxylon (F.Muell.) H.J.Lam". World Flora Online. World Flora Online Consortium. Retrieved 6 September 2021.
  11. ^ "Palaquium galactoxylum {F.Muell.) H.J.Lam". Catalogue of Life. Retrieved 6 September 2021.
  12. ^ "Palaquium galactoxylon". Australian Plant Name Index (APNI). Centre for Plant Biodiversity Research, Australian Government. Retrieved 6 September 2021.
  13. ^ "Palaquium galactoxylum var. salmonense". Global Biodiversity Information Facility. Retrieved 6 September 2021.
  14. ^ "Palaquium galactoxylum var. salmonense (C.T.White) P.Royen". World Flora Online. World Flora Online Consortium. Retrieved 6 September 2021.
  15. ^ "Palaquium galactoxylum var. salmonense (C.T.White) P.Royen". Catalogue of Life. Retrieved 6 September 2021.
  16. ^ "Palaquium galactoxylum var. salmonense (C.T.White) P.Royen". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 6 September 2021.
  17. ^ a b Cooper, Wendy; Cooper, William T. (June 2004). Fruits of the Australian Tropical Rainforest. Clifton Hill, Victoria, Australia: Nokomis Editions. p. 508. ISBN 9780958174213. Retrieved 6 September 2021.

External links[]

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