A lignotuber is a woody swelling of the

root crown A root crown, also known as the root collar or root neck, is that part of a root system from which a stem arises. Since roots and stems have quite different vascular Vascular can refer to: * blood vessels, the vascular system in animals * vascular ...

possessed by some plants as a protection against destruction of the plant stem, such as by fire. Other woody plants may develop basal

burl A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from d ...

s as a similar survival strategy, often as a response to

coppicing Coppicing is the traditional method in woodland management of cutting down a tree to a tree stump, stump, which in many species encourages new Shoot (botany), shoots to grow from the stump or roots, thus ultimately regrowing the tree. A forest ...

or other environmental stressors. However, lignotubers are specifically part of the normal course of development of the plants that possess them, and often develop early on in growth. The crown contains

bud In botany, a bud is an undeveloped or Plant embryogenesis, embryonic Shoot (botany), shoot and normally occurs in the axil of a leaf or at the tip of a Plant stem, stem. Once formed, a bud may remain for some time in a dormancy, dormant conditi ...

s from which new stems may sprout, as well as stores of

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...

that can support a period of growth in the absence of

photosynthesis Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...

. The term "lignotuber" was coined in 1924 by Australian

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

Leslie R. Kerr. Plants possessing lignotubers include many species in Australia; ''

Eucalyptus marginata ''Eucalyptus marginata'', commonly known as jarrah, in Noongar language and historically as Swan River mahogany, is a plant in the Myrtus, myrtle Family (biology), family, Myrtaceae and is endemism, endemic to the Southwest Australia, south-we ...

'' (jarrah), '' Eucalyptus brevifolia'' (snappy gum) and '' Eucalyptus ficifolia'' (scarlet gum) all of which can have lignotubers wide and deep, as well as most mallees (where it is also known as a mallee root) and many ''

Banksia ''Banksia'' is a genus of around 170 species of flowering plants in the family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes, and woody fruiting "cones" and head ...

'' species. Plants possessing lignotubers on the western coast of the USA include

California buckeye ''Aesculus californica'', commonly known as the California buckeye or California horse-chestnut, is a species of buckeye native to California and southwestern Oregon. Description Aesculus californica is a large deciduous shrub or small tree, u ...

coast redwood ''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995: 606–607 is the sole living species of the genus '' Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast redwood, coast ...

, California bay laurel (aka Oregon myrtle), and multiple species of

manzanita Manzanita is a common name for many species of the genus '' Arctostaphylos''. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from Southern British Columbia and Washington to O ...

and ''

Ceanothus ''Ceanothus'' is a genus of about 50–60 species of nitrogen-fixing shrubs and small trees in the buckthorn family (Rhamnaceae). Common names for members of this genus are buckbrush, California lilac, soap bush, or just ceanothus. ''"Ceanothus" ...

''. At least 14 species in the Mediterranean region have been identified as having lignotubers (as of 1993). Lignotubers develop from the

cotyledon A cotyledon ( ; ; "a cavity, small cup, any cup-shaped hollow", gen. (), ) is a "seed leaf" – a significant part of the embryo within the seed of a plant – and is formally defined as "the embryonic leaf in seed-bearing plants, one or mor ...

ary bud in seedlings of several

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

species including cork oak ''

Quercus suber ''Quercus suber'', commonly called the cork oak, is a medium-sized, evergreen oak tree in the section ''Quercus'' sect. ''Cerris''. It is the primary source of cork for wine bottle stoppers and other uses, such as cork flooring and as the core ...

'', but do not develop in several other oak species, and are not apparent in mature cork oak trees. The fire-resistant lignotubers of ''

Erica arborea ''Erica arborea'', the tree heath or tree heather, is a species of flowering plant (angiosperms) in the heather family Ericaceae, native to the Mediterranean Basin and Ethiopia, Kenya and Tanzania in East Africa. It is also cultivated as an o ...

'', known as "briar root", are commonly used to make smoking pipes. The largest known lignotubers (also called "root collar burls") are those of the Coast Redwood ''(

Sequoia sempervirens ''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995: 606–607 is the sole living species of the genus ''Sequoia (genus), Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast ...

)'' of central and northern California and extreme southwestern

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

. A lignotuber washed into Big Lagoon, California, by the full gale storm of 1977 was in diameter and about half as tall and estimated to weigh . The largest

dicot The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, ...

lignotubers are those of the Chinese Camphor Tree, or Kusu ''(

Cinnamomum camphora ''Camphora officinarum'' is a species of evergreen tree indigenous to warm temperate to subtropical regions of East Asia, including countries such as China, Taiwan, Vietnam, Korea, and Japan. It is known by various names, most notably the camph ...

)'' of Japan, China and the Koreas. Ones at the Vergelegen Estate in

Cape Town Cape Town is the legislature, legislative capital city, capital of South Africa. It is the country's oldest city and the seat of the Parliament of South Africa. Cape Town is the country's List of municipalities in South Africa, second-largest ...

, South Africa, which were planted in the late 1600s have muffin-shaped lignotubers up to high and about in diameter. Perhaps the largest lignotuber in Australia would be that of "Old Bottle Butt", a Red Bloodwood Tree (''

Corymbia gummifera ''Corymbia gummifera'', commonly known as red bloodwood, is a species of tree, rarely a mallee, that is endemic to eastern Australia. It has rough, tessellated bark on the trunk and branches, lance-shaped adult leaves, flower buds in groups o ...

'') near

Wauchope, New South Wales Wauchope ( ) is a town in the Mid North Coast region of New South Wales, Australia. It is within the boundaries of the Port Macquarie-Hastings Council area. Wauchope is inland on the Hastings River and the Oxley Highway west of Port Mac ...

, that has a lignotuber about in height and in circumference at breast height. A lignotuber should not be confused with a

xylopodium A xylopodium is a underground storage growth which is multibranched and may cover a circle diameter. They differ from lignotubers which are more compact in form, like a tuber. They are most common in the cerrados of Brazil even including a monoc ...

. Lignotubers are compact, even round. A xylopodium is diffuse and are sometimes called "underground trees". Many plants with lignotubers grow in a shrubby habit, but with multiple stems arising from the lignotuber. The term lignotuberous shrub is used to describe this habit.

References

{{reflist Plant morphology Wildfire ecology

See also

References