|
(Last Modified On 7/19/2013)
|
|
|
|
(Last Modified On 7/19/2013)
|
|
Family
|
SALICACEAE
|
|
Contributor
|
W. G. D'ARCY
|
|
Description
|
Trees or shrubs, dioiceous or rarely monoecious, glabrous or pubescent; branching alternate. Leaves mostly deciduous, alternate, simple, mostly serrate or denticulate, somewhat sclerophyllous, petiolate; stipules deciduous or foliaceous and sometimes persistent; buds covered with one or more deciduous scales. Inflorescences in dense erect or lax racemes (aments, catkins), terminal or on short shoots, the rachis mostly with leafy bracts, the pedicels with small, cuculate, entire bracteoles. Flowers with the perianth represented by basal glands or a disc; male flowers with stamens 2-many, the filaments free or connate, the anthers 2-celled, longitudinally dehiscent; female flowers with the ovary sessile or stipitate, sometimes pubescent, I-locular, the placentas 2-4, parietal, several ovuled, the ovules erect, anatropous, 1(-2)-tegmic, the style solitary or wanting, the stigmas 2-4, often sessile, digitiform. Fruit a capsule, dehiscing to the base into 2-4 recurving valves; seeds mostly numerous, often compressed, copiously long-ciliate (comose), the embryo straight, the' endosperm nuclear, scant.
|
|
Habit
|
Trees or shrubs
|
|
Note
|
The Salicaceae comprises 2 genera, Salix and Populus, best represented in north temperate regions but also widespread in the tropics; they are absent in Australia, the South Pacific and Southeast Asia. Some species grow north of the Arctic Circle. Both genera have wind-dispersed seeds and many specie's are well-adapted to wet habitats. Populus has wind-pollinated flowers while in Salix insects are important in pollination, although reduction of the flowers suggests
|
|
Distribution
|
north temperate regions but also widespread in the tropics
|
|
Note
|
an approach to facultative wind pollination. The family appears to be reduced in floral features from more generalized ancestors. Although a number of pos- sible ancestral relatives have been postulated, no such candidate has received widespread acceptance. The one species of this family known from Panama is also the sole species native in South America. Other species of Salix are known in Central America, and species of Populus occur in southern Mexico.
|
|
Reference
|
Schneider, C. 1917. A conspectus of Mexican, West Indian, Central and South American varieties of Salix. Bot. Gaz. (Crawfordsville) 65: 1-41. Schneider, C. 1919. Notes on American Willows V. The species of the Pleonandrae group. J. Arnold Arbor. 1: 1-32. Schneider, C. 1921. Notes on American Willows XII. A systematic enumeration of the sections, species, varieties and forms of American Willows. J. Arnold Arbor. 3: 61-125.
|
|
Tag
|
|
|
|
Project Name
|
|
Tag
|
|
|
|