Xanthosia Explained

Xanthosia is a genus of flowering plants in the family Apiaceae and is endemic to Australia. It comprises 20 species of shrubs endemic to Australia. Plants in the genus Xanthosia are perennial herbs or small shrubs, the leaves divided, toothed or lobed, (rarely simple), the flowers white, pinkish or pale green and usually arranged in a compound umbel.

Description

Plants in the genus Xanthosia are perennial herbs or small shrubs that usually have divided, toothed, or lobed leaves. The flowers are usually arranged in a compound umbel, opposite leaves or on the ends of short, leafy branches, but sometimes reduced to a single flower. Each main branch of the umbel has an involucral bract and each of the secondary umbels ("umbellules") have 2 or 3 bracteoles at the base. The flowers are white, pinkish or pale green with conspicuous, usually egg-shaped, petal-like sepals, the petals narrow and curved inwards. The fruit is a flattened, oblong or round, non-fleshy schizocarp.^{[1] [2] [3]}

Taxonomy

The genus Xanthosia was first formally described in 1811 by Edward Rudge in the Transactions of the Linnean Society of London, and the first species he described, (the type species) was Xanthosia pilosa.^{[4] [5]} The name Xanthosia means "yellow", referring to the colour of the hairs on some species.^[6]

Species list

The following is a list of species of Xanthosia accepted by the Australian Plant Census at May 2023:^[7]

• Xanthosia atkinsoniana F.Muell. (W.A., N.S.W.)
• Xanthosia candida (Benth.) Steud. (W.A.)
• Xanthosia ciliata Hook. (W.A.)
• Xanthosia collina Keighery (W.A.)
• Xanthosia dissecta Hook.f. (N.S.W., Vic., Tas.) cut-leaved xanthosia
• Xanthosia eichleri J.M.Hart & Henwood (W.A.)
• Xanthosia fruticulosa Benth. (W.A.)
• Xanthosia huegelii (Benth.) Steud. – heath xanthosia (W.A., S.A., Vic.)
• Xanthosia kochii (E.Pritz.) J.M.Hart & Henwood (W.A.)
• Xanthosia leiophylla F.Muell. ex Klatt (S.A., Vic.)
• Xanthosia peduncularis Benth. (W.A.)
• Xanthosia pilosa Rudge – woolly xanthosia (Qld., N.S.W., Vic., Tas.)
• Xanthosia rotundifolia DC. – southern cross (W.A.)
• Xanthosia scopulicola J.M.Hart & Henwood (N.S.W.)
• Xanthosia singuliflora F.Muell. (W.A.)
• Xanthosia sp. Dardanup (B.J. Keighery & N. Gibson 174) (W.A.)
• Xanthosia stellata J.M.Hart & Henwood – star xanthosia (Qld., N.S.W., Vic.)
• Xanthosia tasmanica Domin (W.A., S.A., N.S.W., Vic., Tas.)
• Xanthosia ternifolia J.M.Hart & Henwood (N.S.W., Tas.)
• Xanthosia tomentosa A.S.George (W.A.)
• Xanthosia tridentata DC. rock xanthosia, hill xanthosia (N.S.W., Vic., Tas.)

Notes and References

1. Web site: Hart . J.M. . Henwood . Murray J. . Genus Xanthosia . Royal Botanic Garden Sydney . 3 May 2023.
2. Web site: Duretto . Marco F. . Hart . J.M. . Xanthosia . Royal Botanic Gardens Victoria . 3 May 2023.
3. Web site: Xanthosia . State Herbarium of South Australia . 3 May 2023.
4. Web site: Xanthosia. APNI. 3 May 2023.
5. Rudge . Edward . A description of several species of plants from New Holland. . Transactions of the Linnean Society of London . 1811 . 10 . 2 . 301–302 . 3 May 2023.
6. Book: Sharr . Francis Aubi . George . Alex . Western Australian Plant Names and Their Meanings . 2019 . Four Gables Press . Kardinya, WA . 9780958034180 . 124 . 3rd.
7. Web site: Xanthosia . Australian Plant Census . 3 May 2023.