Proteaceae

Proteaceae Temporal range: Cenomanian–recent PreꞒ Ꞓ O S D C P T J K Pg N [1]
Inflorescence of Protea cynaroides
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Proteales
Family:	Proteaceae Juss.[2]
Genera
About 80, see text

The Proteaceae

Etymology

The name Proteaceae was adapted by Robert Brown from the name Proteae coined in 1789 for the family by Antoine Laurent de Jussieu, based on the genus Protea, which in 1767, Carl Linnaeus derived from the name of the Greek god Proteus, a deity who was able to change between many forms.^[4][5] This is an appropriate image, seeing as the family is known for its astonishing variety and diversity of flowers and leaves.^{[citation needed]}

Description

The genera of Proteaceae are highly varied, with Banksia in particular providing a striking example of adaptive radiation in plants.^[6] This variability makes it impossible to provide a simple, diagnostic identification key for the family, although individual genera may be easily identified.

• Proteaceae range from prostrate shrubs to tall forest trees, of 40 m in height, and are usually of medium height or low or perennial shrubs, except for some Stirlingia species that are herbs. Some species are facultatively deciduous (Embothrium coccineum), rarely acaulescent, the cauline portion of the collar is often thickened (lignotuber). Indumentum of three-celled hairs, sometimes glandular, rarely absent, the apical cell is usually elongated, acute, sometimes equally or unequally bifid.
• mesophyll tissue usually with sclerenchymatous idioblasts, rare secretory cavities. Brachy-paracytic stomata (laterocytic in Bellendena
  ).

Plant stems with two types of radii, wide and multi-serrated or narrow and uni-serrated, phloem stratified or not, trilacunar nodes with three leaf traces (rarely unilacunar with one trace), sclereids frequent; bark with lenticels frequently horizontally enlarged, cork cambium present, usually superficial. Roots lateral and short, often grouped in bundles (proteoid roots) with very dense root hairs, rarely with mycorrhiza.

• Plants usually hermaphroditic, more rarely monoecious, dioecious or andromonoecious.
• Inflorescences very variable, simple or compound, axillary or terminal, lateral flowers solitary or in pairs, rarely with a terminal flower, racemiform, paniculate or condensed, usually with bracts, sometimes converted into leaves or squamiform, forming a type of cone, or with bright colours, forming an involucre or pseudanthium, the peduncles and pedicels sometimes contracted, compacted with the rachis, in some cases the congested inflorescences form super inflorescences (some Alloxylon); very rarely the flowers are solitary and axillary near the end of branches; in species with lignotubers the flowers sometimes grow from these and pass through the soil (geophytes).
• style usually developed, stigma small or in the shape of a terminal or sub terminal disk or even lateral and oblique, often indented, papilous, moist or dry, ovules 1–100 or more per carpel, anatropous, hemianatropous, amphitropous or orthotropous, mostly hemitropous, bitegmic, crassinucellate, chalaza with a ring of vascular bundles, the funiculus is occasionally absent and the ovule is fused to the placenta, marginal placentation
  with various dispositions or apical.
• Fruit dehiscent or indehiscent, in achene or nucule, follicle, drupe (with lignified endocarp) or falsely drupal (with lignified internal mesocarp), sometimes similar to a caryopsis as it is fused to the wall of the ovary and the testa, often lignified and serotinous; the fruit from the same inflorescence are sometimes fused forming a syncarp.
• Seeds 1-many, sometimes winged, flat to rounded, with endosperm absent, present in Bellendina, endotesta with an unusual layer containing crystals of calcium oxalate that is rarely absent, well differentiated embryo, straight, dicotyledonous, but often with 3 or more (up to 9) large cotyledons, often auriculate.
• Pollen in monads, triangular in polar view, (2-)3(−8)-aperturate, usually isopolar and triporate, biporate in Embothrium and the tribe Banksieae, colpoidate in Beauprea, spherical in Aulax and Franklandia or strongly anisopolar in some species of Persoonia; the openings of the former's tetrads follow Garside's Law.^{[clarification needed]}
• Chromosomal number: n=5, 7, 10–14, 26, 28; sizes range from very small (average of 1,0 μm) to very big (average of 14,4 μm) according to species; x=7, 12.

Flowers

Generally speaking, the diagnostic feature of Proteaceae is the compound

Many of the Proteaceae have specialised

as mammals and birds ingest them. Some African and Australian rodents are known to accumulate fruit and seeds of these plants in their nests in order to feed on them, although some manage to germinate.

Distribution

Proteaceae are mainly a Southern Hemisphere family, with its main centres of diversity in Australia and South Africa. It also occurs in Central Africa, South and Central America, India, eastern and south eastern Asia, and Oceania.^[8] Only two species are known from New Zealand, although fossil pollen evidence suggests there were more previously.^[9]

It is a good example of a Gondwanan family, with taxa occurring on virtually every land mass considered a remnant of the ancient supercontinent Gondwana, except Antarctica. The family and subfamilies are thought to have diversified well before the fragmentation of Gondwana, implying all of them are well over 90 million years old. Evidence for this includes an abundance of proteaceous pollen found in the Cretaceous coal deposits of the South Island of New Zealand. It is thought to have achieved its present distribution largely by continental drift rather than dispersal across ocean gaps.^[10]

Phytochemistry

No conclusive studies have been carried out on the chemical substances present in this broad family. The genera

flavonols (kaempferol, quercetin and myricetin) and arbutin. Alkaloids are usually absent. Iridoids and ellagic acid are also absent. Saponins and sapogenins can be either present or absent in different species. Many species accumulate aluminium

.

Uses and cultivation

Many traditional cultures have used Proteaceae as sustenance, medicine, for curing animal hides, as a source of dyes, firewood and as wood for construction. Aboriginal Australians eat the fruit of

Telopea. This use has resulted in the introduction of exotic species that have become invasive; examples include the hakea willow (Hakea salicifolia) and the silky hakea (Hakea sericea

) in Portugal.

Two species of Macadamia are cultivated commercially for their edible nuts.

Gevuina avellana (Chilean hazel) is also cultivated for its edible nuts, in Chile and New Zealand, and they are also used in the pharmaceutical industry for their humectant properties and as an ingredient in sunscreens. It is the most cold-resistant of the tree families that produce nuts.^{[citation needed]} It is also planted in the British Isles and on the Pacific coast of the United States for its tropical appearance and its ability to grow in cooler climates

.

Many Proteaceae species are cultivated by the

nursery industry as barrier plants and for their prominent and distinctive flowers and foliage. Some species are of importance to the cut flower industry, especially some Banksia and Protea species. Two species of the genus Macadamia

are grown commercially for edible nuts.

Sugarbushes (

Cape Floral Kingdom, the smallest but richest plant kingdom for its size and the only kingdom contained within a single country. The other main groups of plants in fynbos are the Ericaceae and the Restionaceae. South African proteas are thus widely cultivated due to their many varied forms and unusual flowers. They are popular in South Africa for their beauty and their usefulness in wildlife gardens

for attracting birds and useful insects.

The species most valued as ornamentals are the trees that grow in southern latitudes as they give landscapes in

temperate climates a tropical appearance; Lomatia ferruginea (Fuinque), Lomatia hirsuta (Radal) have been introduced in Western Europe and to the western United States. Embothrium coccineum (Chilean Firetree or Notro) is highly valued in the British Isles for its dark red flowers and can be found as far north as the Faroe Islands

at a latitude of 62° north.

Among the banksias, many of which grow in temperate and Mediterranean climates, the vast majority are shrubs; only a few are trees that are valued for their height. Among the tallest species are: B. integrifolia with its subspecies B. integrifolia subsp. monticola, which is noteworthy as the plants that form the subspecies are the tallest trees of the banksias and they are the more frost-resistant than other banksias, B. seminuda, B. littoralis, B. serrata; among those that can be considered small trees or large shrubs: B. grandis, B. prionotes, B. marginata, B. coccinea and B. speciosa; all of these are planted in parks and gardens and even along roadsides because of their size. The rest of the species of this genus, around 170 species, are shrubs, although some of them are valued for their flowers.

Another species that is cultivated in some parts of the world, although it is smaller, is Telopea speciosissima (Waratah), from the mountains of New South Wales, Australia.

Some temperate climate species are cultivated more locally in Australia for their attractive appearance: Persoonia pinifolia (pine-leaved geebung) is valued for its vivid yellow flowers and grape-like fruit. Adenanthos sericeus (woolly bush) is planted for its attractive soft leaves and its small red or orange flowers. Hicksbeachia pinnatifolia (beef nut, red bauple nut) is commonly planted for its foliage and edible nuts.

Parasites

The Proteaceae are particularly susceptible to certain parasites, in particular the oomycete Phytophthora cinnamomi, which causes severe root rot in the plants that grow in Mediterranean climates. Fusarium oxysporum causes a disease called fusariosis in roots that causes a yellowing and wilting, with serious ecological damages to woodland plants and economic losses in plants of commercial interest. Other common infections are caused by species of Botryosphaeria, Rhizoctonia, Armillaria, Botrytis, Calonectria and other fungi.

Conservation status

The

IUCN^[11] considers that 47 Proteaceae species are threatened, of which one species, Stenocarpus dumbeensis Guillaumin, 1935, from New Caledonia, is thought to be extinct. The species of this family are particularly susceptible to the destruction or fragmentation of their habitat, fire, parasitic diseases, competition from introduced plants, soil degradation and other damage provoked by humans and their domesticated animals. The species are also affected by climate change

.

Fossils

The Proteaceae have a rich fossil record, despite the inherent difficulties in identifying remains that do not show diagnostic characteristics. Identification usually comes from using a combination of brachy-paracytic stomata and the unusual

Palaeocene of South America and the north east of Australia. The fossil record of some areas, such as New Zealand and Tasmania, show a greater biodiversity for Proteaceae than currently exists, which supports the fact that the distribution of many taxa has changed drastically with the passage of time and that the family has suffered a general decline, including high levels of extinction during the Cenozoic.^{[citation needed}

]

Taxonomy

First described by French botanist Antoine Laurent de Jussieu, the family Proteaceae is a fairly large one, with around 80 genera, but less than 2,000 species. It is recognised by virtually all taxonomists. Firmly established under classical Linnaean taxonomy, it is also recognised by the cladistics-based APG and APG II systems. It is placed in the order Proteales, whose placement has itself varied.

A classification of the genera within Proteaceae was made by

Symphionematoideae, Proteoideae and Grevilleoideae.^[14] In 2008 Mast and colleagues updated Macadamia and related genera in tribe Macadamieae. Furthermore, Orites megacarpus was found not to be within the genus Orites, nor in the tribe Roupaleae, instead in the tribe Macadamieae, hence given the new species name Nothorites megacarpus.^[15]

The full arrangement, according to Weston and Barker (2006) with the updates to genera from Mast et al. (2008), is as follows:

Family Proteaceae

Subfamily

Bellendenoideae

Bellendena

Subfamily Persoonioideae

Tribe

Placospermeae

Placospermum

Tribe

Persoonieae

Persoonia

Subfamily

Symphionematoideae

Agastachys — Symphionema

Subfamily Proteoideae

incertae sedis

Eidothea — Beauprea — Beaupreopsis — Dilobeia — Cenarrhenes — Franklandia

Tribe Conospermeae

Subtribe

Stirlingiinae

Stirlingia

Subtribe Conosperminae

Conospermum — Synaphea

Tribe Petrophileae

Petrophile — Aulax

Tribe Proteeae

Protea — Faurea

Tribe Leucadendreae

Subtribe

Isopogoninae

Isopogon

Subtribe

Adenanthinae

Adenanthos

Subtribe Leucadendrinae

Leucadendron — Serruria — Paranomus — Vexatorella — Sorocephalus — Spatalla — Leucospermum — Mimetes — Diastella — Orothamnus

Subfamily Grevilleoideae

incertae sedis

Sphalmium — Carnarvonia

Tribe

Roupaleae

incertae sedis

Megahertzia — Knightia — Eucarpha — Triunia

Subtribe

Roupalinae

Roupala — Neorites — Orites

Subtribe

Lambertiinae

Lambertia — Xylomelum

Subtribe

Heliciinae

Helicia — Hollandaea

Subtribe

Floydiinae

Darlingia — Floydia

Tribe

Banksieae

Subtribe

Musgraveinae

Musgravea — Austromuellera

Subtribe

Banksiinae

Banksia

Tribe

Embothrieae

Subtribe

Lomatiinae

Lomatia

Subtribe

Embothriinae

Telopea

Subtribe

Stenocarpinae

Stenocarpus — Strangea

Subtribe Hakeinae

Opisthiolepis — Buckinghamia — Hakea — Grevillea — Finschia

Tribe

Macadamieae

Subtribe

Macadamiinae

Macadamia — Lasjia — Nothorites — Panopsis — Brabejum

Subtribe Malagasiinae

Malagasia — Catalepidia

Subtribe Virotiinae

Virotia — Athertonia — Heliciopsis

Subtribe

Gevuininae

Cardwellia — Euplassa — Gevuina — Bleasdalea — Hicksbeachia — Kermadecia

References

1. ^ "Proteales". www.mobot.org. Retrieved 16 June 2023.
2. hdl:10654/18083
   .
3. doi:10.11646/phytotaxa.261.3.1
   .
4. On the Proteaceae of Jussieu
   ". Transactions of the Linnean Society of London 10:15–226, 1811.
5. ^ Jussieu, Antoine Laurent de, Genera plantarum secundum ordines naturales disposita, juxta methodum in Horto Regio Parisiensi exaratum, anno M.DCC.LXXIV. Paris, 1789. pp. 78–80 Archived 16 February 2016 at the Wayback Machine.
6. S2CID 2835600
   .
7. ^ Watson, L. & Dallwitz, M. J. (1992). "Proteaceae". The Families of Flowering Plants: Descriptions, Illustrations, Identification, Information retrieval. Retrieved 26 June 2006.
8. ^ ^{a b} Orchard, Anthony E. (ed.). "Proteaceae". Flora of Australia, Volume 16: Elaeagnaceae, Proteaceae 1. Melbourne: Australian Biological Resources Study / CSIRO Publishing. Archived from the original on 31 October 2006. Retrieved 26 June 2006. {{cite book}}: |author= has generic name (help)
9. doi:10.1071/SB97019
   .
10. ISBN 978-90-5103-136-2
    .
11. ^ IUCN 2006. 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 22 February 2007
12. ^ Rozefelds, Andrew C.; Dettmann, Mary E.; Clifford, H. Trevor. "Xylocaron lockii F.Muell. (Proteaceae) fruits from the Cenozoic of south eastern Australia". Kanunnah. 1: 91–102.
13. doi:10.1111/j.1095-8339.1975.tb01644.x
    .
14. ^
    doi:10.7751/telopea20065733
    . Retrieved 30 March 2010.
15. PMID 21632410
    .

• Weston, P.H. (2007). "Proteaceae". Kubitzki, K. (Editor). The Families and Genera of Vascular Plants. IX. Flowering Plants – Eudicots. Springer-Verlag: Berlín.
  ISBN 978-3-540-32214-6
  .
• Hoot, S.B. & Douglas, A.W. (1998). "Phylogeny of the Proteaceae based on atpB and atpB-rbcL intergenic spacer region sequences". Australian Systematic Botany. 11 (4): 301–320.
  doi:10.1071/sb98027
  .
• Ramsey, H.P.. (1963). "Chromosome numbers in the proteaceae". Australian Journal of Botany. 11 (1): 1–20.
  doi:10.1071/BT9630001
  .
• Watson, L. & Dallwitz, M.J. (1992). "The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 29th July 2006". Retrieved 31 January 2007.
• Brown, R. On the Proteaceae of Jussieu
  Proceedings of the Linnean Society
  10:15-216.

External links

• Images of Proteaceae from the Australian National Botanical Gardens
• Map