The Chromosome Number in Ipomoea and Related Genera

Cytomorphological Studies in Convolvulaceae

“…I. heder acea, a slender and hairy twiner, is cultivated throughout the Indian plains and hills up to 2,000m for its showy flowers ranging in colour from white to violet. Four populations differing in their flower colour (white, pink, pinkish-blue and blue) were studied and these uniformly showed n=15, in line with the similar earlier records for the species (Kano 1929, Walcott 1937, King and Bamford 1937, Ting et al 1957, Sharma and Datta 1958, Nakajima 1963, Jones 1964. The chromosomes/ bivalents were comparatively larger in the white flowered type and smaller in the blue flowered type.…”

“…From the genus Merremia, M. dissecta and M. aegyptia both with n=15, 2n=30 were studied and corroborate the earlier cytological records (King and Bamford 1937, Jones 1964, 1968 for the former and (Thombre 1959, Miege 1962, Jone 1968 for the latter species. Lewis et al (1967) recorded 2n=28 for M. aegyptia indicating thereby its occurrence as two cytological types.…”

“…I. mutabilis (n=15+O-1B) was cytologically unin vestigated earlier while the previous cytological finds of n=15, 2n=30 are confirmed in I. hirsutula (Jones 1964), I. nil (Nagao 1928, Yasui 1928, U 1930, King and Bam ford 1937, Nakajima 1963, Jones 1964, 1968, Lewis et al 1967) and I. purpurea (Yasui 1928, Kano 1929, King and Bamford 1937, Sharma and Datta 1958, Diers 1961, Nishiyama et al 1961, Nakajima 1963, Jones 1964, 1968. I. congesta (n=15) though in agreement with the earlier identical reports (King and Bamford 1937, Ting et al 1957, Sharma and Datta 1958, Jones 1964, 1968) is at variance with 2n=32 record by Rao (1940) who investigated this species as I. learii Paxt. Taking the taxonomic identity of Rao's material to be authentic, I. congesta seems to exist as two cytological types with n=15 and 16.…”

“…I. hederifolia seems to exist as two cytological types with n=14 (Nakajima 1931, Kagawa and Nakajima 1933, King and Bamford 1937, Walcott 1937, Sharma and Datta 1958, Jones 1964 and n=15 (Kano 1929, Borgmann 1964, I. quamoclit uniformly shows n=15 (Kano 1929, Nakajima 1931, Kagawa and Nakajima 1931, King and Bamford 1937, Sharma and Datta 1958, Jones 1964 n=14, 2n=28 (King and Bamford 1937, Walcott 1937, Sharma and Datta 1958, Jones 1964.…”

“…batatas, is known to occur as a number of morphological variants (Nishiyama 1971) and exists as different cytological types, 2n=30 (Nishyama 1971), 2n=60 (Nishiyama 1971), 2n=84 (Kano 1929) and 2n=90 (King and Bamford 1937, Rao 1947, Ting and Keher 1953Sharma and Datta 1958, Nishiyama et al 1961, Jones 1965, Wedderburn 1967, Nishiyama 1971 (Jones 1964, Sharma andDatta 1958) for the former and (Jones 1964, Miege 1962 for the latter species.…”