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 In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body ...

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 dor ...

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

coppicing Coppicing is a traditional method of woodland management which exploits the capacity of many species of trees to put out new shoots from their stump or roots if cut down. In a coppiced wood, which is called a copse, young tree stems are repeate ...

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 embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...

s from which new stems may sprout, as well as stores of starch that can support a period of growth in the absence of

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

. The term "lignotuber" was coined in 1924 by Australian botanist Leslie R. Kerr. Plants possessing lignotubers include many species in Australia: ''

Eucalyptus marginata ''Eucalyptus marginata'', commonly known as jarrah, djarraly in Noongar language and historically as Swan River mahogany, is a plant in the myrtle family, Myrtaceae and is endemic to the south-west of Western Australia. It is a tree with rough ...

'' (Jarrah), ''

Eucalyptus brevifolia ''Eucalyptus brevifolia'', commonly known as snappy white gum or northern white gum, is a tree that is endemic to northern Australia. It has smooth, powdery white bark, lance-shaped adult leaves, buds arranged in group of seven, white flowers and ...

'' (snappy gum) and ''

Eucalyptus ficifolia ''Corymbia ficifolia'' ( syn. ''Eucalyptus ficifolia'', commonly known as the red flowering gum, is a species of small tree that is endemic to the south-west of Western Australia. It has rough, fibrous bark on the trunk and branches, egg-shape ...

'' (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 in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes, and fruiting "cones" and heads. ''Banksias'' range ...

'' 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 It is a large deciduous shrub or small tree, up to tall, with ...

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, coastal ...

, 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 Or ...

and ceanothus. At least 14 species in the

Mediterranean region In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and wa ...

have been identified as having lignotubers (as of 1993). Lignotubers develop from the

cotyledon A cotyledon (; ; ; , gen. (), ) is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The num ...

ary bud in seedlings of several

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

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 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'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast redwood, coastal ...

)'' of central and northern

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

and extreme southwestern

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. 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, t ...

lignotubers are those of the Chinese Camphor Tree, or Kusu ''( Cinnamomum camphora)'' of Japan, China and the

Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...

s. Ones at the Vergelegen Estate in

Cape Town Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

, 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 Macquar ...

that has a lignotuber about in height and in circumference at breast height. 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

Plant morphology Wildfire ecology {{botany-stub

See also

References