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Family Description- the Fagaceae (Beech Family)


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Family Description- The Fagaceae (Beech Family)




I. Taxonomy

Division Magnoliophyta

Class Magnoliopsida

Subclass Hamamelidae

Order Fagales

Family Fagaceae

(http://ag.arizona.edu/classes/rnr202/taxtour/menu.html)
II. Description

Habit
The Fagales are all trees or shrubs with simple leaves usually arranged alternately (rarely opposite or whorled). Each plant generally contains tiny flowers of each sex (monoecious); unisexual flowers are primarily pollinated by the wind.(Encyclopaedia Britannica)



Leaves

The beeches are tardily deciduous trees, although some have rather thick, leathery leaves. Many have a tendency to retain their leaves, although in a dry, lifeless state, even through the winter, especially when young. In Lithocarpus and Chrysolepis, and some species of Quercus, the plants are evergreen with thick, leathery-textured, usually smooth-margined leaves.

Outside of the tropics and warm temperate areas, most members of the family are deciduous, and the leaves are frequently deeply lobed or at least coarsely toothed at the margins. Whereas many deciduous trees in temperate areas produce one major flush of new leaves each spring, many species of oaks and some plants in other families in temperate areas continue to produce new leaves throughout the growing season. These two features, the lack of a well-developed abscission layer in the leaf petiole and the production of leaves throughout the summer, are interpreted as indicating an origin for the family in the tropics or subtropics, where equitable conditions would allow growth to occur throughout the year.

The rapid decrease in the diversity of species of Fagaceae north of about latitude 35 to 40 N lends support to this hypothesis. The special conditions in the Mediterranean area--summer dryness and winter rains--which also are found in part of western North America, give a dry habit character to members of the Fagales occurring there, including such features as small leathery leaves that are spiny or hairy. (Encyclopaedia Britannica)

Flower

Of the extant genera of Fagaceae, Chrysolepis is considered to exhibit the most primitive features in the pistillate (female) flowers. The basic structure of the pistillate inflorescence is believed to be a three-flowered dichasium (an older central flower and a pair of opposite lateral branches bearing flowers). (Encyclopaedia Britannica) The male flowers have a 4-7 lobed perianth of tepals and 4-40 stamens and are usually grouped in pendulous catkins. The female flowers are solitary or in small clusters. They have a 4-6 lobed perianth of tepals, and are often subtended by a series of bracteoles comprising an involucre. The single compound pistil of 3-6 carpels has an inferior ovary with 3-6 locules and two basal or nearly basal ovules in each locule.





Quercus sp. oak.

Small brownish stipules are visible on the new growth at the upper right. Note the pendulous catkins with many small male flowers.

A cluster of 3 female flowers is visible in the photo on the right. Note the series of pinkish bracteoles comprising an involucre that hides the lower portion of each ovary. Just below the 3-branched style, at the top of each green ovary, tiny pinkish perianthsegments are visible.

(http://www.botany.hawaii.edu/faculty/carr/fag.htm)




Fruit

Three families--Fagaceae, Betulaceae, and Balanopaceae (Balanopsidaceae)--make up the order. (The latter family is placed in a separate order, the Balanopales, by Armen Takhtajan.) The most distinguishing feature of the Fagales is the cupule (hull) subtending or surrounding the fruit. The structure is believed to be of a different origin in each of the three families: in the Fagaceae it is derived from a highly modified and reduced branch system with its associated modified leaves or bracts, at least in the genus Quercus. The Fagaceae and Betulaceae have pendulous ovules and dry fruits that are either nuts or samaras and bear a single seed.

(Encyclopaedia Britannica)



Leaves and Fruit of Oak Tree (Watson, L./Dallwitz, M. J.,1992 onwards)

III. Geography

One can find plants of the Fagacaea family in the frigid, temperate and sub-tropical zone. They are found almost everywhere except the tropical South America and tropical South Africa.

(Watson, L./Dallwitz, M. J.,1992 onwards).

IV. Representative genera and species

The family Fagaceae, the beeches, contains about 1,000 species unevenly distributed among 9 genera (10 genera if Nothofagus is retained as a genus in the Fagaceae). The Fagaceae can be divided into 2 subfamilies.

The first, Fagoideae, contains the genera Fagus, or beeches; Quercus, or oaks; Colombobalanus; Formanodendron; and Trigonobalanus.

The second, Castaneoideae, contains Castanea, Castanopsis, Chrysolepis (which some experts include in the genus Castanopsis), and Lithocarpus. Trigonobalanus verticillata, restricted to Borneo, Sumatra, Celebes, and the Malay Peninsula, is unusual in the family in having the leaves arranged in whorls.


Fagus (the beeches) is a genus of about 10 species in the Northern Hemisphere, with the greatest diversity in China and Japan, where about 7 species are found. A single variable species, F. grandifolia (the American beech), occurs in eastern North America and Mexico, and another, F. sylvatica, is found in Europe.
Fagus sylvatica

(http://www.wisc.edu/botit/img/bot/401/)


The largest genus in the Fagoideae, and in the entire Fagaceae, is the genus Quercus (the oaks), with about 450 species, mostly limited to the warmer parts of the Northern Hemisphere. The greatest concentrations of species of oaks are in the southeastern to southwestern United States and Mexico; in eastern Asia (China and Japan); and in the area from the Mediterranean to Caucasia.
In the Castaneoideae, the 12 or so species of the genus Castanea also show a worldwide distribution in temperate areas of the Northern Hemisphere, again with the greatest diversity in eastern Asia. In Europe one can find Castanea sativa.



Fruits and Habit of Castanea sativa (http://www.wisc.edu/botit/img/bot/401)

The 2 species of Chrysolepis are confined to the western United States. The 2 remaining genera in the subfamily, Lithocarpus, with perhaps as many as 300 species, and Castanopsis, with about 120 species, are almost exclusively restricted, to eastern and southeastern Asia and the Indomalesian region (a region composed of India, Malaysia, New Guinea, Indonesia, the Philippines, and Borneo), mostly west of Wallace's Line (i.e., Borneo, Java, and Bali, but not extending to Celebes).


Extant species of Nothofagus are scattered throughout southern South America, Australia, New Zealand, New Caledonia, and the mountains of New Guinea.

(Encyclopaedia Britannica)



V. Uses

The oaks and birches are sources of some of the world's most valuable timbers. In both temperate and tropical America, many species of oak provide highly durable timber for use in construction, flooring, veneer, and millwork, as well as in the building of ships and boats.

Since the time of Confucius, cork has been used for a variety of purposes, from insulation to decoration. Commercial cork is obtained almost exclusively from the bark of the cork oak, Quercus suber, native to and cultivated in the Mediterranean region; however, other species also produce cork.




Bark of Quercus suber

(http://www.wisc.edu/botit/img/bot/401/)


The bark is first stripped from the trees when they are about 20 years old, although the first quality cork is not produced for another 8 to 10 years. Trees may produce cork for an average of 150 years.

Oaks are also valuable sources of tannins (chemical compounds valued for, among other things, their ability to condition animal skins into leather.

Other chemical products were obtained at one time; for example, methyl alcohol, acetic acid, creosote, guaiacol, and tar were extracted from Fagus; and acetic acid was obtained from Quercus robur.

Many members of the Fagales produce edible fruits, some of which have been cultivated since ancient times. The European (Castanea sativa) and Chinese (C. mollissima) chestnuts are economically important crops, although susceptibility to the chestnut blight fungus has somewhat diminished production of C. sativa.

Although not a commercial crop, the acorns produced by most species of oak (Quercus) are edible, but many require some preparation to remove the tannins. In North America, acorns were used extensively by the native Indians; the nuts of the "sweet" members of the white oak group were often consumed directly, while the bitter nuts of other species were ground and soaked before being made into mush or bread. Throughout the world, several species are used as feed for livestock and are important to local wildlife populations.

The nuts of several Lithocarpus and Castanopsis species are a food source in their home countries of China and southeast Asia.

Members of the Fagales are also known to be harmful. The pollen of almost all of the temperate genera--Alnus, Betula, Carpinus, Corylus, and Ostrya in the birch family, and Fagus and especially Quercus in the beech family--have been reported to cause allergic reactions.


(Encyclopaedia Britannica)

VI. Other


Threats

According to the 1997 IUCN Red List of Threatened Plants 12% of total species in Fagaceae are threatened (Data based on 6-8 genera/ 800 species)



IUCN category Species

Extinct (Ex): --

Possibly extinct (Ex/E): 1

Endangered (E): 13

Vulnerable (V): 21

Rare (R): 36

Indeterminate (I): 25

Number threatened (Ex/E, E, V, R, I): 96

(Walter, K.S./Gillett, H.J.,1998).

Poems

And many strokes, though with a little axe,

Hew down and fell the hardest-timbered oak

(‘3rd Henry the Sixth’, ii., 1)


I have seen tempests when the scolding winds

Have rived the knotty oaks

(‘Julius Caesar’, i., 3)
All the elves for fear,

Creep into acorn-cups, and hide them there

(‘Midsummer Night’s Dream’, i., 1)
(Watson, L./ Dallwitz, M. J.,1992 onwards).


VII. Literature used


"Fagales" Encyclopaedia Britannica Online.



<http://members.eb.com/bol/topic?eu=120816&sctn=1>

[Accessed April 5 2000].


Watson, L., and Dallwitz, M. J. (1992 onwards). ‘The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval.’ Version: 19th August 1999. http://biodiversity.uno.edu/delta/.

Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1995 onwards, 1998), and Watson and Dallwitz (1991)


Walter, K.S. and Gillett, H.J. [eds] (1998). 1997 IUCN Red List of Threatened Plants.Compiled by the World Conservation Monitoring Centre. IUCN - The World Conservation Union, Gland, Switzerland and Cambridge, UK. lxiv + 862pp.

http://www.wcmc.org.uk/cgi-bin/nph-readfile.pl/parent=wcmcname/filename=FAMSTAT?290277
http://www.botany.hawaii.edu/faculty/carr/fag.htm


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