Morphology and anatomy of the Cephalocereus columna-trajani cephalium: why tilting? |
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Authors: | M Vázquez-Sánchez T Terrazas S Arias |
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Institution: | (1) Programa de Botánica, Colegio de Postgraduados, Montecillo, Estado de México, 56230, México;(2) Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México. 70-633, 04510, México, D.F;(3) Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México. 70-633, 04510, México, D.F |
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Abstract: | The morphology and anatomy of the Cephalocereus columna-trajani flowering region was described and compared with data on other species. The vegetative and reproductive regions were described
in detail. The results showed that after the flowering region is differentiated, morphological changes take place which are
correlated with anatomical changes. The flowering region in this species is termed a lateral cephalium because of its reduced
interareolar space, increased areole size and abundant long bristles and trichomes in the areoles. Periderm development near
the apical meristem, lack of chlorenchyma and a delay in xylem fiber differentiation are also traits characteristic of a lateral
cephalium. The lateral cephalium of C. columna-trajani shared the same combination of morpho-anatomical characters with its sister taxon, C. senilis, except for the number of ribs in the cephalium. Both species survive in high temperature environments and their cephalium
faces north; however, only C. columna-trajani tilts, thus we hypothesize that incorporation of fewer ribs associated with periderm development in the cephalium contributes
to stem tilting. |
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Keywords: | Cactaceae Cephalocereus columnar flowering region lateral cephalium Oaxaca periderm pseudocephalium Puebla |
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