The Lawrencia Page

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Synonymy of Asterotrichion, Gynatrix and Lawrencia

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Lawrencia berthae (F. Muell.) Melville
Lawrencia buchananensis Lander
Lawrencia chrysoderma Lander
Lawrencia cinerea Lander
Lawrencia densiflora (Baker f.) Melville
Lawrencia diffusa (Benth.) Melville
Lawrencia glomerata Hook.
Lawrencia helmsii (F. Muell. & Tate) Lander
Lawrencia repens (S. Moore) Melville
Lawrencia spicata Hook.
Lawrencia squamata Nees
Lawrencia viridigrisea Lander

Introduction

Lawrencia is a genus with the family Malvaceae. The 12 or so species of the genus are endemic to Australia (including Tasmania), where they are primarily found in arid and saline habitats. 6 species are endemic to Western Australia, and 1 to Queensland; the remainder are more widely distributed in Australia.

Classification

The genus was introduced by Hooker in 1840, with Lawrencia spicata as the type species. It was name in honour of Robert William Lawrence, a settler and botanical collector in northern Tasmania, who provided specimens to Hooker [1]. Lawrencia is closely related to Plagianthus and Hoheria (New Zealand endemic genera) and also Asterotrichion (a Tasmanian endemic genus) and and Gynatrix (an Australian endemic genus), and together with Asterotrichion, Gynatrix and some species of Hoheria has in the past been placed in Plagianthus. These genera (the Plagianthus alliance) belong to tribe Malveae wherein, together with Sida hookeriana (also Australian), they form a clade, which combined with the northern South American Sidasodes and the eastern North American Sida hermaphrodita is the sister group to the remainder of subtribe Abutilinae [2]. This wider group may be worthy of recognition as subtribe Plagianthinae.

There are 12, or perhaps more, species; the Western Australian Herbarium lists 12 named and 3 unnamed species, and the Northern Territory Herbarium lists another 2 unnamed species (which cannot be assumed to be distinct from the Western Australian species.)

Asa Gray proposed the name Wrenciala (an anagram) as a replacement for Lawrencia, on the grounds that the latter was too close to the prior name Laurencia. This proposal has not been adopted.

The genus was revised by Melville in 1966 [a], and by N.S. Lander in 1985 [b]. The former segregated a genus Selenothamnus consisting of L. helmsii and L. squamata. The latter divided Lawencia into subgenera Lawrencia and Panifex (type L. berthae); subgenus Lawrencia into sections Lawrencia and Selenothamnus; and section Selenothamnus into series Selenothamnus (type L. squamata) and Halophyton (type L. diffusa). L. helmsii also falls into section Selenothamnus; apart from that I don't have details as to where the other species fall. [3]

Lawrencia berthae (F. Muell.) Melville
 Showy Lawrencia

A spreading, low-growing (to 80 cm), white-flowered shrub, native to south western Australia, from Albany eastwards [1], and also to Southern Australia, New South Wales and Victoria.

Synonyms of Lawrencia berthae include  Plagianthus berthae F.Muell..

Lawrencia buchananensis Lander
 Lake Buchanan blue bush

Endemic to the western shore of Lake Buchanan in Queensland.

Lawrencia chrysoderma Lander

A spreading, straggly or erect, white-, cream- or yellow-flowered, succulent shrub, growing to 30 to 120 cm in height. [1]

Lawrencia cinerea Lander

An ascending, white- or cream-flowered shrub, from to 35 to 130 cm in height. [1]

Lawrencia densiflora (Baker f.) Melville
 golden-spike

An ascending, white-, cream-, yellow- or green-flowered, perennial herb, growing to 7 to 60 cm in height, from intermediate latitudes in the west of Western Australia. [1]

Synonyms of Lawrencia densiflora include  Plagianthus densiflorus Baker f..

Lawrencia diffusa (Benth.) Melville

A dwarf, prostate, white-flowered, perennial herb of shrub, with a height of 5 to 20 mm, and a spread of 5 to 30 cm., from south west Australia. [1]

Synonyms of Lawrencia diffusa include  Plagianthus diffusus Benth..

Lawrencia glomerata Hook.
 small golden-spike

An ascending, white-, cream-, yellow- or green-flowered, fleshy-stemmed, perennial herb or shrub, growing from 10 to 100 cm in height [1]. Its stems range from glabrous to densely tomentose with single, 2-branched and stellate hairs. The leaves have toothed margins. The lower leaves are petiolate with a petiole up to 5 cm long, and an obtuse apex. The upper leaves are sessile, with acute or 3-lobed apices. The calyx is up 12mm long, and the petals up to 9mm long. [4]

It is widely distributed in Australia, where it is found in all five mainland states and in the Northern Territory. [3]

Synonyms of Lawrencia glomerata include  Plagianthus glomeratus Hook..

Lawrencia helmsii (F. Muell. & Tate) Lander
 Dunna Dunna

An erect, yellow- or green-flowered shrub, superficially reminiscent of a cactus, grow to between 30 and 150 cm in height, native to the interior of south western Australia. [1]

Synonyms of Lawrencia helmsii include  Plagianthus helmsii F.Muell. & Tate and Selenothamnus helmsii (F.Muell. & Tate) Melville .

Lawrencia repens (S. Moore) Melville

A spreading, prostate, white-, yellow- or green-flowered, perennial herb, with a height of from 1 to 15 cm, and a spread of 5 to 55 cm, native to the Kalgoorlie region of Western Australia [1].

Synonyms of Lawrencia repens include  Plagianthus repens var. pentandra E.Pritz and Plagianthus repens S.Moore.

Lawrencia spicata Hook.
 candle saltmallow, Salt Lawrencia

Lawrencia spicata is a perennial herb of salt-marshes found from Tasmania, through Victoria and South Australia, to the southwest of Western Australia. It has a rosette of coarsely serrate, oblong to ovate-oblong, leaves with truncate bases, to about 1" in length, with much longer petioles. From this arises an erect flowering spike of sessile white or yellow flowers, clustered in groups of one to three in the axils of fleshy, acuminate, bracts. This spike can reach as much as 5 foot in height, or as little as 1 or 2 feet.

Synonyms of Lawrencia spicata include  Plagianthus spicatus var. pubescens Benth. and Plagianthus spicatus Benth..

Lawrencia squamata Miq.
 grey fanleaf, Thorny Lawrencia, thorny saltmallow

An erect, spiny, white-, yellow-, red- or purple-flowered shrub with twisted stems, growing to from 20 to 100 cm, or exceptionally 150 cm in height [1], native to arid regions (especially to the south) of all mainland states and the Northern Territory, and naturalised in Tasmania 5.

Synonyms of Lawrencia squamata include  Halothamnus microphyllus F.Muell., Lawrencia incana (J.M.Black) Melville, Lawrencia microphyllus F.Muell., Plagianthus incanus J.M. Black, Plagianthus squamatus (Nees) Benth. and Selenothamnus squamatus (Nees) Melville .

Lawrencia viridigrisea Lander

An ascending, white- or yellow-flowered shrub, reaching from 20 to 100 cm in height, found in northwestern Australia, in both Western Australia and the Northern Territories, especially along the west and north west coasts of Western Australia.

Lawrencia species Anna Plains (Western Australia)
Lawrencia species Glen Helen (Northern Territory)
Lawrencia species Mulein Station (Western Australia)
Lawrencia species small fruits (Western Australia)
Lawrencia species The Granites (Northern Territory)

These are undescribed species listed on the websites of the corresponding herbaria. I cannot be certain that all these species are distinct, each from the other.

The Anna Plains plant is an upright, white-flowered, perennial herb, reaching 80 cm in height, found on the margins of a semi-saline coastal plain in north west Australia. The Mulein Station plant is an erect, yellow-flowered, annual herb, reaching 1 m in height, found inland in the mid-west of Western Australian (Carnarvon and Gascoyne districts). The small fruited plant is an upright, spreading, yellow- or green-flowered, annual or perennial herb, growing to between 45 and 100 cm in height, found on calcareous or saline loams in the southern half of the interior of Western Australia. [1]

Images

References

  1. FloraBase (Western Australian Herbarium)
  2. J.A. Tate et al, Phylogenetic Relationships Within the Tribe Malveae (Malvaceae, subfamily Malvoideae) as Inferred from ITS Sequence Data, Am. J. Bot. 92(4): 584-602 (2005)
  3. Australian Plant Name Index (APNI)
  4. New South Wales Flora Online
  5. Key to Tasmanian Dicots (Lawrencia)
  6. Kubitzki & Bayer, Malvaceae, in Kubitzki & Bayer, Fam. Gen. Vasc. Plants V: (2003)
  7. Cowie & Albrecht, Checklist of NT Vascular Plant Species (2005)

Bibliography

  1. Melville, Contributions to the Flora of Australia: VII. Generic delimitation in the Plagianthus complex, Kew Bulletin 20: 511-516 (1966)
  2. N.S. Lander, Revision of the Australian genus Lawrencia Hook. (Malvaceae : Malveae), Nuytsia 5(2): 201-272 (1985)

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© 2004, 2006, 2007 Stewart Robert Hinsley