|typical screwpine habit|
The Pandanaceae are a family of flowering plants native to the tropics of the Old World. Such a family has been widely recognized by taxonomists. Pandanaceae are trees or climbing or scrambling shrubs distributed in the Old World tropics and are adapted from sea level in salted beaches to mountain cloud forest, and riverine forest habitat. The fruit is a drupe.
It is a large family of four genera, in about 900 species, of trees, shrubs and root climbers found in the Old World tropical and subtropical regions, from West Africa through the Pacific. A highly variable genus complex, stems have aerial prop roots to provide support and display sympodial branching. The stems bear prominent leaf scars. This family are palmlike dioecious trees and shrubs Often called Palms, but these plants are not closely related to palm trees. The leaves are very long and narrow, sheathing, simple, undivided, with parallel veins; the leaf margins and adaxial midribs are typically very prickly. The plants are dioecious. Both male and female flowers lack calyx and corolla. Inflorescences are terminally borne. The flowers are minute, and are arranged in a racemose spadix with a subtended spathe or bracts which may be brightly colored. Male flowers contain numerous stamens arranged in a raceme or umbel with free or fused filaments. Female flowers have a superior ovary usually of many carpels in a ring but may be reduced to a row of carpels or a single carpel. Fruits are berries or multilocular drupes, and edibles.
They grow fairly quickly. The plants are prominent in cultural, health, and economic importance in the Pacific, second only to coconut on atolls in Pacific culture and tradition, including local medicine.
Hundreds of cultivated varieties, collectively recognized in the Pacific, but specific to numerous independent cultural traditions, are known by their local names and characteristics of fruits, branches, and leaves. They grow wild mainly in seminatural vegetation in littoral habitats throughout the tropical and subtropical Pacific, where they can withstand drought, strong winds, and salt spray. They propagate readily from seed, but are also widely propagated from branch cuttings by local people.
Pandanaceae are an ancient family of dioecious monocots dating from the early to mid-Cretaceous, and comprising four genera: Martellidendron, Sararanga, Freycinetia and Pandanus. A cladistic analysis of Pandanaceae based on DNA sequences of four cpDNA fragments (the trnL intron and three intergenic spacers, trnL-F, trnS-ycf9 and atpB-rbcL) was used to elucidate intergeneric relationships within the family. The results show Pandanus, as currently circumscribed, was biphyletic, with members of the Indian Ocean subgenus Martellidendron sister to the Indo-Malesian genus Freycinetia in a clade that also includes the Malesian genus Sararanga, and the remaining members of Pandanus form a separate, well-supported clade. Martellidendron is thus recognized as a distinct genus, thereby circumscribing a monophyletic Pandanus. Martellidendron contains seven species. The high level of morphological differentiation between the genera of Pandanaceae suggests rapid early radiation as seen in other monocot groups. The molecular data also indicate the distinct lineages of Pandanaceae in the Indian Ocean basin are likely the result of both vicariance and more recent step-wise long-distance dispersal from Asia across the Indian Ocean, e.g., monocarpellate spiniform species in lowland eastern Madagascar.
The APG II system, of 2003 (unchanged from the APG system, 1998), also recognizes this family, and assigns it to the order Pandanales in the clade monocots. It consists of four genera, of which Pandanus (the screwpines) is the most important:
- Freycinetia Gaudich.
- Martellidendron (Pic.Serm.) Callm. & Chassot
- Pandanus Parkinson
- Sararanga Hemsl.
- Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013–06–26.
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