| Alabama croton | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Euphorbiaceae |
| Genus: | Croton |
| Species: | C. alabamensis |
| Binomial name | |
| Croton alabamensis | |
| Varieties | |
C. a. var. alabamensis Contents | |
Croton alabamensis, known as Alabama croton, is a rare species of flowering plant in the spurge family, Euphorbiaceae, that is endemic to Texas and Alabama in the Southeastern United States. [2]
The Alabama croton is a semi-evergreen monoecious shrub that reaches a height of 5–35 dm [3] The loose, multi-stemmed thickets [4] it forms are colloquially known as "privet brakes". [5] C. alabamensis is the northernmost shrubby species of the genus Croton in North America [6] and the largest species of Euphorbiaceae native to North America. [7]
Leaves are clustered at branch tips and lack stipules. The petiole is 0.6–2 cm. Glands are absent at its apex. Leaf blades are elliptic, ovate, or oblong and measure 3–10 × 1.5–5 cm. Blade margins are typically entire, sometimes undulate. The base is rounded to obtuse, while the apex is acute, rounded, or emarginate. Abaxial surfaces are silvery or coppery and densely lepidote, while adaxial surfaces are green and sparsely lepidote. [3] When crushed, leaves emit a fragrance similar to a mixture of banana and apple. [8]
The inflorescence is a bisexual or unisexual raceme 2–4.5 cm in length. Racemes have 0–15 staminate flowers and 0–10 pistillate flowers. [3] Flowers are pollinated by bees. [5] Pistillate flowers are formed earlier and are lower in the raceme than staminate flowers. [9] Flowering occurs in the spring, with peak flowering occurring in mid-March. [10]
The pedicels of staminate flowers are 2.2–4 mm long. The 5 sepals are 1.1–2.9 mm in length and have a lepidote abaxial surface. The 5 petals are oblong-ovate and 2–3.1 mm in length with an abaxial surface that is glabrous except at margins, where it is stellate-ciliate. Staminate flowers have 10–22 stamens. [3]
Pedicels of pistillate flowers are 2.2–7.5 mm in length, increasing to 7–11 mm when in fruit. The 5 sepals measure 2–4.5 mm in length, have entire margins, an incurved apex, and a lepidote abaxial surface. The 5 petals are pale green, ovate, and 2–3.5 mm in length. The ovary is 3-locular. There are 3 styles 2–5 mm long, usually unbranched, rarely bifid, with 3 terminal segments (sometimes 6). [3]
The fruit is a smooth capsule measuring 1.6–2.5 × 2–3 mm. The columella is 3-angled. [3] Capsules ripen by June, after which seeds are explosively dehisced. [10] Seeds are shiny and measure 6.7–8 × 5.2–6 mm. [3] Seeds require cold stratification in order to germinate. [10]
There are two varieties that are separated by more than 1000 km: [6] [11]
Both varieties are found on a plateau or in foothills bordering the Atlantic Plain in limestone, shale, or dolomitic outcrops and adjacent outwashes. [6]
The nominate variety is found on dry slopes, bluffs, and outcroppings with thin, alkaline soil in Tuscaloosa and Bibb County, Alabama. [5] [10] In Tuscaloosa County, the plant occurs in the Black Warrior River watershed north of Tuscaloosa, which is part of the Cumberland Plateau. [6] In Bibb County, it is found in Ketona dolomite glades near the Cahaba River [14] within the Alabama Ridge and Valley physiographic province. [6] Associated woody vegetation includes Juniperus virginiana , Quercus muehlenbergii , Pinus palustris , Sabal minor , and Phyllanthopsis phyllanthoides . [14]
Texabama croton is restricted to the eastern Edwards Plateau [11] and southern Cross Timbers [15] within Travis, Bell and Coryell counties. Within this limited range, it has a very patchy distribution and is abundant in the few niches where it occurs and is absent elsewhere. C. alabamensis var. texensis inhabits pockets of deep soils within forested, mesic canyons and upland oak mottes [16] at elevations of 200 to 400 m. [17]
Croton alabamensis belongs to the monotypic section Alabamenses within the subgenus Quadrilobi. [18] Its closest relatives inhabit primarily mesic regions in the Neotropics, such as members of the former genus Moacroton, which are restricted to serpentine soils in Cuba. [19] Molecular clock analysis suggests it split from its closest relative in the middle Eocene, approximately 41 million years ago. The Alabama and Texas varieties diverged much more recently in the Quaternary, possibly due to allopatric speciation. [6]
The Alabama croton is grown as an ornamental for its form and foliage [20] and is valued for its drought tolerance, low maintenance, and herbivore resistance. [21] Although normally forming loose clonal colonies, it can be trained as a single-trunked, dense shrub. [22] The plant is hardy to USDA Hardiness Zone 6a. [23] It can be propagated via layering, cuttings [21] and stratified seeds. [24] Cultivated specimens occur at the Mt. Cuba Center in Hockessin, Delaware, [25] [26] the University of Alabama Arboretum in Tuscaloosa, Alabama, [8] the Donald E. Davis Arboretum at Auburn University in Auburn, Alabama, [27] the Scott Arboretum at Swarthmore College in Swarthmore, Pennsylvania, [28] Birmingham Botanical Gardens, [29] the JC Raulston Arboretum at North Carolina State University in Raleigh, North Carolina, [30] the Brooklyn Botanic Garden, [31] Jenkins Arboretum in Devon, Pennsylvania, [32] Texas Discovery Gardens in Dallas, Texas, [33] the Lady Bird Johnson Wildflower Center in Austin, Texas, [34] Atlanta Botanical Garden, [35] the Sarah P. Duke Gardens at Duke University in Durham, North Carolina, [36] and Cheekwood Botanical Garden and Museum of Art in Nashville, Tennessee. [37]
Croton alabamensis was discovered in July 1877 by state geologist Eugene Allen Smith on limestone bluffs at Pratt's Ferry near Centreville, Alabama during a geological survey. Specimens of the plant were sent to botanist and pharmacist Charles T. Mohr, who then passed them to botanist Alvan Wentworth Chapman. Chapman formally described C. alabamensis as a new species in the second edition of his Flora of the Southern United States . [10] C. alabamensis var. texensis was discovered in April 1989 at Fort Cavazos in Coryell County by Carol Beardmore and Rex Wahl. [38] Two months later, plants were independently discovered by Chuck Sexton approximately 70 km to the south on the Post Oak Ridge [39] of the future Balcones Canyonlands National Wildlife Refuge in northwestern Travis County. [38] [40] Steve Ginzbarg, a botanist at the University of Texas at Austin, formally described it as a distinct variety of C. alabamensis in 1992. [39]
Croton alabamensis and its nominate variety are considered Vulnerable by NatureServe, [1] [12] while C. a. var. texensis is considered Imperiled. [13] Threats include habitat loss and forestry practices. [1] In Alabama, protected populations of the plant occur within The Nature Conservancy's Pratt's Ferry Preserve, [41] the University of West Alabama's Cahaba Biodiversity Center, [42] and the Cahaba River National Wildlife Refuge. [43] In Texas, Balcones Canyonlands National Wildlife Refuge, Pace Bend Park, and Fort Cavazos are home to protected populations of the plant. [6] [15]
Aleurites is a small genus of arborescent flowering plants in the Euphorbiaceae, first described as a genus in 1776. It is native to China, the Indian Subcontinent, Southeast Asia, Papuasia, and Queensland. It is also reportedly naturalized on various islands as well as scattered locations in Africa, South America, and Florida.
The Donald E. Davis Arboretum, in Auburn, Alabama, United States, is a public native plants museum, and botanical arboretum with educational facilities, event spaces, and a conservation program. Its grounds, covering 13.5 acres of Auburn University's campus, include cataloged living collections of associated tree and plant communities representative of Alabama's ecosystems, among which is mixed oak forest, carnivorous bog, and longleaf pine savanna. The living collections include more than 1,000 plant types, including 500 different plant species, with over 3,000 cataloged specimens. The Arboretum contains over a mile (2 km) of interwoven walking trails that meander through various southeastern biotopes.
Spathiostemon is a genus of trees in the Euphorbiaceae family. It is native to the Bismarck Archipelago, New Guinea, Wallacea and Southeast Asia. The trees grow between 10 and 20m tall, often in secondary forest. The wood is sometimes used.
Ostrya virginiana, the American hophornbeam, is a species of Ostrya native to eastern North America, from Nova Scotia west to southern Manitoba and eastern Wyoming, southeast to northern Florida and southwest to eastern Texas. Populations from Mexico and Central America are also regarded as the same species, although some authors prefer to separate them as a distinct species, Ostrya guatemalensis. Other names include eastern hophornbeam, hardhack, ironwood, and leverwood.
Codiaeum variegatum is a species of Codiaeum, a genus of flowering plants, in the Euphorbiaceae. Initially described by Carl Linnaeus in 1753, it is native to Australasia and Oceania, from Malaysia and Indonesia in the north through northeastern Australia, as well as many Southeast Asian and South Pacific islands, growing in open forests and scrub.
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Acalypha rhomboidea is a plant in the spurge family, Euphorbiaceae.
Euphorbia corollata is an herbaceous perennial plant in the family Euphorbiaceae that is native to North America. A common name for the species is flowering spurge. It has a milky sap that can cause skin and eye irritation in some people. It grows up to 1 m (3 ft) tall, with smooth stems and light green leaves arranged alternately or in whorls. Leaves are about 10 mm wide and 75 mm (3 in) long. Each stem terminates in a panicle 20 to 25 mm across. Flowers are about 6 mm across and consist of one pistillate and several staminate flowers surrounded by five white bracts - not petals but formed from the involucre at the base of the flowers. Flowering spurge blooms from June to September.
Ambrosia chenopodiifolia is a species of ragweed known by the common names San Diego bursage and San Diego bur ragweed. It is native to the Mexican states of Baja California and Baja California Sur, as well as to Orange and San Diego Counties it int US State of California. It is a member of the coastal sage scrub plant community.
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Cyclachaena xanthiifolia, known as giant sumpweed, or rag sumpweed is a North American plant species in the sunflower family, Asteraceae. It is the only species in the genus Cyclachaena. Giant sumpweed is believed to be native to the Great Plains but is now found across much of southern Canada and the contiguous United States, though rarely in the Southeast.
Carex gholsonii is a plant species native to Florida, Georgia, Alabama, North Carolina and South Carolina.
Acalypha ostryifolia, sometimes spelled ostryaefolia, is a plant in the family Euphorbiaceae and is commonly known as hophornbeam copperleaf, hornbeam copperleaf, or pineland threeseed mercury, is an annual herb of the copperleaf genus Acalypha. It is a native of North and Central America and is generally considered a weed.
Prunus alabamensis, the Alabama cherry or Alabama black cherry, is an uncommon or rare species of tree in the rose family endemic to parts of the Southeastern United States. It occurs in the states of Alabama, Florida, Georgia, Mississippi, and South Carolina. It is closely related to and found wholly within the range of Prunus serotina, the black cherry, a much more common and widespread species of Prunus that is also native to the region. Alabama cherry is sometimes considered to be a variety of Prunus serotina, however most authors treat it as a distinct species.
Carya pallida, sand hickory, or pale hickory is a species of hickory native to the southeastern United States. It is a perennial, dicotyledonous plant which prefers rocky or sandy habitats. The sand hickory can reach heights of up to 30m, but its typical height is between 9-24m. In an open area, Carya crowns are usually towering and slim. The sand hickory nut is edible and consumed by various organisms.
Stillingia sylvatica, known as queen's-delight or queen's delight, is a species of flowering plant in the family Euphorbiaceae. It was described in 1767. It is endemic to the south-central and southeastern United States, growing in sandy areas such as sandhills and pine flatwoods.
Tragia betonicifolia, commonly called betonyleaf noseburn, is a species of flowering plant in the spurge family (Euphorbiaceae). It is native to North America, where it is primarily found in the South-Central region of the United States extending north into Kansas and Missouri, with disjunct populations east in Tennessee. Its typical natural habitat is dry areas with sandy or rocky soil, in glades, prairies, bluffs, and dry woodlands.
Croton alabamensis var. texensis is a variety of Croton alabamensis that is endemic to the state of Texas in the United States. It is commonly known as the Texabama croton.
Aporosa octandra is a species of plant in the family Phyllanthaceae found from Queensland and New Guinea to Indonesia, Zhōngguó/China and India. It is a highly variable plant with 4 named varieties. Its wood is used in construction and to make implements, its fruit is edible. The Karbi people of Assam use the plant for dyeing, textile colours have quite some significance in their culture.
