Tuesday, May 28, 2019

The Families of Flowering Plants :: essays research papers

Asphodelaceae(Aloe Family)CLASSIFICATIONDahlgren et al. (1985) divided the Monocotyledons into several superorders of which the Liliiflorae is the largest. The order Asparagales is the largest of the five orders within Liliiflorea. sensation of the families within Asparagales recognized by Dahlgren and his co-workers was Asphodelaceae (Chase et al. (2000). Asphodelaceae consists of the sub-families, the Asphodeloideae and the Alooideae. The Alooideae consists of six genera of which Aloe is the largest. The sub-family Alooideae are noned for their spectacular secondary growth, a characteristic used to define the Alooideae as monophyletic. On the other hand, about workers within the taxa have considered the above two subfamilies were for sometime, considered to be separate families, the Asphodelaceae and Alooideae (Dagne and Yenesaw 1994). Determining the proper phylogeny was difficult because some authors have argued that Aspodeloideae is not a monophyletic group. Also, the Aspode loideae are more varied and share a great deal of morphological similarities between other groups (Chase et al. 2000). The latest genesis of chemical information on species belonging to these two groups is believed to reveal the relationships among the various taxa and to assist in establishing taxonomic classifications at various levels (Dagne and Yenesaw 1994). However, there is still not strong enough evidence suggesting both sub-families should not be included in a single family, the Asphodelaceae (Bisrata 2000). MORPHOLOGYAsphodelaceae is a unadorned family from other liliod monocot groups by a combination of several morphological and reproductive features simultaneous microsporogensis, atypical ovular structure, lacking steroidal saponins, producing seeds with arils, and the general comportment of anthraquinones. Basic morphological features of genera within the Asphodelaceae consist of mostly herbs, shrubs, and sometimes arborescent, which grows into woody forms with trunk s that can grow up to several meters high. The leaves are organisation is alternate, spiral or 2-ranked that usually form rosettes at base or ends of the branches. The leaves are often thick and succulent with parallel venation. The succulent aloes variegate in size and morphology from the dwarf rosettes (Adams et al. 2000). Vascular parcel of lands are arranged in rings around mucilaginous parenchyma tissue, the bundles have parenchymatous aloin cells in inner bundle sheath near the phloem poles. The association of aloin cells and central gelatinous zones are synapomorphic for species with Alooideae (Judd et al. 1999). The perianth is usually bisexual and showy, with 6 distinct to strongly connate, non-spotted tepals. Reproductive bang parts have 6 distinct stamens and 3 connate carpels and a superior ovary that contain nectaries in septa.

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