Lindera

Lindera
Lindera melissifolia
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Magnoliids
Order:	Laurales
Family:	Lauraceae
Genus:	Lindera Thunb.
Species
See text.
Synonyms
Benzoin Boerh. ex Schaeff. Daphnidium Nees Iteadaphne Blume Parabenzoin Nakai Sinosassafras H.W.Li

Lindera is a genus of about 80-100^[1] species of flowering plants in the family Lauraceae, mostly native to eastern Asia but with three species in eastern North America.^[1][2] The species are shrubs and small trees;^[2] common names include Spicewood, Spicebush, and Benjamin Bush.

Overview

Colored leaves of Lindera

They are dioecious, with male and female flowers on separate trees. They are aromatic evergreen or deciduous trees or shrubs. Many botanical species are having similar foliage due to convergent evolution in wet lands. Some species are in danger of extinction due to over exploitation as medicinal plants or timber extraction and also for loss of habitat. The leaves can be either deciduous or evergreen depending on species,^[2] and are alternate, entire or three-lobed, and strongly spicy-aromatic. Lindera species are no exception among the Lauraceae; Lindera genus have small flowers, hard to detect and collect and often overlooked or ignored when plants easier to collect or with showier flowers are at hand.

Lindera are woody perennial plants. Their leaves are opposite or alternate with three main veins. The leaves can be either deciduous or evergreen depending on species,^[2] and are alternate, entire or three-lobed, and strongly spicy-aromatic. The inflorescences are composed of 3 to 15 flowers existing pseudo-umbels. They are sessile or on short shoots. The flowers are from greenish to white, greenish-yellow, yellowish, with star shape and six tepals.^[2] Male and female flowers commonly are on different plants. The flowers themselves are trifoliate or irregularly built, in separate sexes. Six equal-faceted bracts, but they may also be missing completely or decrease during the flowering season. The male flowers have nine to 15 fertile stamens, the innermost circle of stamens can be found at the base of the stamens glands. Usually the stamens are longer than the anthers, which in turn consist of two chambers and directed inwards or sideways. The vestigial ovary is very little or absent. The base of the flower is small and flat. The female flowers have a varying number of staminodes. The pollination is done by bees and other insects. The most striking are its fruits. The fruit has a small fruit cup, or is free on a thickened stem. The fruit is a small red, purple or black drupe containing a single seed, dispersed mostly by birds. Many species reproduce vegetatively by stolons. Species with strictest ecological requirements and resistant habits, which can survive in conditions that are not appropriate, such as lack of light due to competition with other species but occurring too across a gradient of canopy cover including full sun , intermediate shade, and full shade. Most populations have been observed under closed overstory canopies of bottomland forests, and consequently, considered a shade-tolerant species, occurs also along the margin of a seasonally flooded depressional wetland dominated by Nyssa sylvatica, and Taxodium ascendens, as also in the dense shade of Quercus laurifolia, Acer rubrum, and Liquidambar styraciflua, in the Aultman Forest; The genus grow too in herbaceous zone with little canopy cover adjacent to a cypress dome surrounded by pine plantations, and the other beneath a canopy of A. rubrum, N. sylvatica, and T. ascendens.^[3] The ecological characteristics of Lindera are similar to those of Litsea and are considered as a parallel evolution in Lauraceae.^[4]

Ecology

A related vegetal community evolved millions of years ago on the supercontinent of Gondwana, and species of this community are now found mostly on several separate areas of the Southern Hemisphere, including South America, Africa, New Zealand, Australia and New Caledonia. Because of the special lack of worldwide knowledge about the family lauraceae in general, very little is known about their diversity. The species is found in forests that face threats of destruction by human deforestation.

The lindera genus come from relict species living in a more warmer and humid climate conditions in continents and therefore, more distributed in the Tertiary. The main centers are found inhabiting wet forests or wet coastal temperate forest in low-altitude in cloud forest habitat. Some species of genus have adapted to more extreme conditions but mostly depending on favorable soil edaphic conditions, as presence of aquifers, groundwater periodic flows, etc.

The patterns of speciation in the Lauraceae family, where lindera genus belong, indicate that since the onset of aridification on the continents 15 million years ago, rainforest diversified in species numbers with the majority of species the product of vicariance. One of the products of aridification is the current island like archipelagos of rainforests along the planet. The fragmentation of once more continuous rainforest facilitated isolation of populations and this likely caused the increase in the rate of speciation as found today. Lindera genus responded to favourable climatic periods and expanded across the available habitat. Before modern flood control was imposed along the Mississippi River and its tributaries, historic floods may have been an important mechanism in fruit and/or seed dispersal over long distances or for creating suitable conditions for seedling establishment. Although the fruit of pondberry sinks in water after a short time, the seed with the pulp removed will float for a day or sometimes longer.^[5]

The lindera genus features are similar to other species no related, due to convergent evolution. Plants of laurel forests habitat, must adapt to high rainfall and humidity. Some species are adapted by developing leaves that repel water. Laurophyll or lauroide leaves are characterized by a generous layer of wax, making them glossy in appearance, and narrow, pointed oval in shape with an apical mucro, or 'drip tip', which permit the leaves to shed water despite the humidity, allowing perspiration and respiration from plant. Deciduous lindera lose all of their leaves for part of the year depending on variations in rainfall. In deciduous tropical lauraceae, leaf loss coincides with the dry season in tropical, subtropical and arid regions. In temperate or polar climates the dry season is due to the inability of the plant to absorb water available to it only in the form of ice. Furthermore, it is common that the dispersal of seeds in many lauraceae species are due to birds that swallow them, so also the fruit and berries are often similar to attract birds. Birds, are important dispersal agents. The hermit thrush swallows the whole fruit and later regurgitates the seed, indicating that it is an important seed disperser. Mammals may also be potential dispersers of genus seeds, including the raccoon (Procyon lotor) and opossum (Didelphis virginiana).^[5] Historically, in North America, the black bear (Ursus americanus) have been important to seed dispersal.

Some species of lindera genus are widespread relics of the laurisilva forests that originally covered much of the Earth when the climate was more humid. Disappeared during the glaciations, some species re-colonize large areas when the weather was favorable again. With the drier and harsher of the climate during the Pliocene era, the laurel forests gradually retreated, and were replaced by the more drought-tolerant sclerophyll plant communities familiar today. Some species are stoloniferous, and they did probably always been rare species since the onset of aridification on the continent. Knowledge of its ecology is limited. The ecological requirements of the species, are those of the laurel forest and like most of their counterparts laurifolia in the world, they are vigorous species with a great ability to populate the habitat that is conducive, but they are not so widespread geographically as in the past. In warmer areas occurs in bottomland hardwood forests. Most to north are found on the bottoms and edges of shallow seasonal ponds in old dune fields, but in more dry areas they occurs in low habitat along a river. Sunlight at the different sites ranges from deep shade to almost full sun. Most Lindera colonies occur in light shade beneath a forest canopy, but a few grow in almost full sunlight. The genus appears to be able to occupy widely different habitats as long as its requirements for water are met. Habitat fragmentation severely affects dioecious species like pondberry because populations with plants of a single sex can only vegetatively reproduce. With significant habitat loss, plants become ever more isolated, lessening the likelihood that pollinators will travel from male to female plants.

Bog spicebush, Lindera subcoriacea was first described in 1983 by Wofford. It is a shrub that grows to 4 m and has simple, alternate leaves. Male and female flowers occur on separate shrubs in early spring and the bright red drupes persist into fall. It typically occurs in boggy areas along streams with sphagnum moss, bay trees, and titi. It is sporadically distributed from Virginia to Louisiana and east to northern Florida. There are less than 100 occurrences most of which consist of only a few genetic individuals. Currently bog spicebush is ranked G2/S1 with only two known Florida occurrences, one on Eglin Air Force Base in Okaloosa County and the other on the campus of the University of West Florida in Escambia County.^[6]

Plants only vegetatively reproducing, are clones expanding vegetatively through stolons, and this mechanism of vegetative reproduction is the principal way that colonies develop. Stems usually live 6 or 7 years, and when a stem dies it is usually replaced by a new stem that grows from the base of the plant. Thus, mature colonies often include some dead stems intermingled with numerous live stems.

In some colonies vegetatively reproducing, as in some pondberry colonies, despite the regular production of mature fruit, virtually no seedlings have been observed at any of the known sites. The Sexual reproduction need male and female trees. This sexual reproduction is need for long-range dispersal and genetic diversity.

Lindera species are used as food plants by the larvae of some Lepidoptera species including The Engrailed.

Species

Selected species

Lindera aggregata Lindera akoensis Lindera angustifolia Lindera benzoin - Common Spicebush, Benjamin Bush Lindera chienii Lindera chunii Lindera communis Lindera doniana Lindera erythrocarpa Lindera flavinervia Lindera floribunda Lindera foveolata Lindera fragrans Lindera glauca Lindera gracilipes Lindera guangxiensis Lindera kariensis Lindera kwangtungensis Lindera latifolia Lindera limprichtii Lindera longipedunculata Lindera lungshengensis Lindera megaphylla

Lindera melissifolia - Southern Spicebush Lindera metcalfiana Lindera monghaiensis Lindera motuoensis Lindera nacusua Lindera neesiana Lindera obtusiloba Lindera praecox Lindera prattii Lindera pulcherrima Lindera reflexa Lindera robusta Lindera rubronervia Lindera setchuenensis Lindera strychnifolia Lindera subcoriacea - Bog Spicebush Lindera supracostata Lindera thomsonii Lindera tienchuanensis Lindera tonkinensis Lindera umbellata Lindera villipes

References

1. ^ ^{a b} 1. Lindera Thunberg, Flora of North America
2. ^ ^{a b c d e} 5. Lindera Thunberg, Flora of China
3. ^ http://www.amjbot.org/content/92/4/682.full.pdf
4. ^ http://en.cnki.com.cn/Article_en/CJFDTOTAL-YOKE198502000.htm
5. ^ ^{a b} Smith, Carl G., III; Hamel, Paul B.; Devall, Margaret S.; Schiff, Natan M. 2004. Hermit thrush is the first observed dispersal agent for pondberry (Lindera melissifolia). Castanea 69(1):1-8.
6. ^ http://www.fnai.org/PDF/Population%20Surveys%20of%20Rare%20Lauraceae%20Species%20to%20Assess%20the%20Effect%20of%20Laurel%20Wilt%20Disease%20in%20Florida.pdf