Floral morphology of the family compositae
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Vernonia anthelmintica (Linn.) Willd., tribe Vernonieae, family Compositae has been studied. The cypsela has dimorphic pappus, 20 longitudinal ribs (10 primary and 10 secondary), and two types of hairs developing from single epidermal cells on surface. Certain features of vasculature of floret observed in this taxon have been considered as intermediate between relatively primitive and highly advanced conditions known in the family. Others elucidate further that the ovary is bilocular with axile placentation at base in which region the ovule is attached, and unilocular with parietal placentation in the remaining portion, and also that the ovule possibly belongs to one of the two carpels, which alone is fertile, and is an organ morphologically double in nature. The pappus has been regarded as a longitudinally dismembered calyx tube.
The tissue of the ovule outside nucellus differentiates into an endothelium, a periendothelial zone, and an outer zone. In the mature seed the thickned outer epidermis and remmants of a few subjacent layers form the outer zone, and endothelium redued to a pellicle, the inner zone of the seed coat. The jacket layer of the endosperm persists between the seed coat and the dicotyledonous, orthorrhizal embryo.
The pericarp development resembles that of most other Compositae in an early differentiation of the ovary wall into two zones, and later breakdown of a major part of the inner zone. But it is quite characteristic in other respects, especially, the peripheral chin of firovascular bundles which forms its main mechanical zone.
KeywordsSeed Coat Outer Zone Sieve Tube Floral Morphology Megaspore Mother Cell
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- Bentham, G. 1873. Notes on the classification, history and geographical distribution of Compositae. Jour. Linn. Soc. Bot.13: 335–577.Google Scholar
- Bhargava, H.R. 1935. Contribution to the morphology ofEclipta erecta L. Proc. Indian Acad. Sci. B1: 325–336.Google Scholar
- Briquet, J. 1916. Etudes carpologiques sur les generes de ComposeesAnthemis, Ormanis, etSahtolina. Ann. Conserv. et Jard. Bot. Geneve.18–19: 257–313.Google Scholar
- Carlquist, S. 1961a. Comparative Plant Anatomy. Holt, Rinehart and Winston, New York.Google Scholar
- Carlquist, S. 1961b. Compositae.In Peter Gray, ed., the Encyclopedia of the Biological Sciences, New York.Google Scholar
- Davis, Gwenda L. 1966. Systematic Embryology of the Angiosperms. John Wiley and Sons, Inc., New York.Google Scholar
- Deshpande, P.K. 1960. A reinvestigation of the endosperm inCaesulia axillaris Roxb. Curr. Sci.29: 56–57.Google Scholar
- — 1962. A reinvestigation of the endosperm inTridax procumbens L. Curr. Sci.31: 113–114.Google Scholar
- Good, R. 1931. Some evolutinary problems presented by certain members of the Compositae. Jour. Bot.69: 299–305.Google Scholar
- — 1956. Features of Evolution in the Fowering Plants Longman, Green and Co., London.Google Scholar
- Johansen, D.A. 1940. Plant Microtechnique. McGraw-Hill Inc., New York.Google Scholar
- Lavialle, P. 1912. Reserches sur le développement de l'ovarie en fruit chez les Composées. Ann. Sc. nat. bot. Ser. 9,15: 39–152.Google Scholar
- Lund, S. 1872–73. Le Calice des Composées. Pt. I, Botanisk Tidsskrift Bd. II, p. 121. Pt. II, Botanisk Tidsskrift Bd. II, p. 260.Google Scholar
- Manilal, K.S. 1963. Morphological studies in the family Compositae. Thesis, Univ. Saugar, Sagar (India).Google Scholar
- — 1966. Studies in the floral anatomy of Compositae. I. The tribes Vernonieae and Eupatorieae. Proc. Nat. Acad. Sci.36: 513–526.Google Scholar
- Misra, S. 1964. Floral morphology of the family Compositae. II. Development of the seed and fruit inFlaveria repanda Lag. Bot. Mag. Tokyo77: 290–296.Google Scholar
- Mitra, J. 1947. A contribution to the embryology of some Compositae. J. Indian Bot. Soc.26: 105–123.Google Scholar
- Padmanabhan, D. 1962. A reinvestigation of the endosperm and endothelium inTridax procumbens L. Phytomorphology12: 356–361.Google Scholar
- Ramiah, N. andM. Sayeeduddin. 1958. Homology of the pappus in the light of trichome distribution. Curr. Sci.27: 402–404.Google Scholar
- Small, J. 1919. The origin and development of Compositae. New Phytol., rep. no. 11., London.Google Scholar
- Tiagi, B. andS. Taimni. 1963. Floral morphology and Embryology ofVernonia cinerescens Schult. andV. cinerea Less. Agra Univ. J. Res.12: 123–138.Google Scholar