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Evolutionary and taxonomic studies of Ipomoea L. sect. Involucratae B AK . & R ANDLE (Convolvulaceae) in Nigeria
Author(s) -
Ogunwenmo K. O.
Publication year - 1999
Publication title -
feddes repertorium
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.24
H-Index - 25
eISSN - 1522-239X
pISSN - 0014-8962
DOI - 10.1002/fedr.19991100709
Subject(s) - sepal , bract , biology , ipomoea , botany , convolvulaceae , taxon , chromosome number , inflorescence , chromosome , pollen , karyotype , genetics , stamen , gene
Taxonomic circumscription of the Nigerian material of Ipomoea pileata is suggested owing to its uniqueness from the Asian and other African specimens. Cotyledon size, presence or absence of inner, sepal‐like bracts, sepal's shape, colour and size of corolla, stigma colour and number of flower per involucre‐bract among others are diagnosticable. Evolutionary mechanisms leading to speciation in Ipomoea sect. Involucrutae include shortening of life cycle with development of long seed dormancy period, variation of flower opening and closing periods, reduction in size and number or loss of floral part(s), inbreeding and geographical isolation. Chromosome counts revealed 2 n = 30 with different lengths ( P < 0.01). A new taxon. Ipomoea involucrata P. B EAUV .var. involucrata f. bicolor O GONWENMO f. nova is described.