Chromosome numbers and taxonomy in Cryptocoryne (Araceae). II

Abstract

Chromosome numbers for 38 species of Cryptocoryne are reported, 16 of which have not been reported earlier. About 90% of the species of Cryptocoryne have now been investigated cytologically. On the basis of chromosome numbers, morphology, and distribution, it is possible to distinguish some 24 groups within the species investigated. The chromosome numbers represent a heteroploid series which is based on the (secondary) base numbers 10, 11, 14, 15, 17, and 18. Evidence is given that 2n = 36 is the more primitive one. Evolution on the chromosome level has most likely gone in the direction of a reduction in numbers. Two new species, Cryptocoryne amicorum De Wit & N. Jacobsen and C. keei N. Jacobsen, are described.

Hybrids and the Flora of Thailand revisited: Hybridization in the South-East Asian genus Cryptocoryne (Araceae)

“…since the middle of the 1970s we have been working with various aspects of Cryptocoryne: taxonomy (for an overview see Bastmeijer, 2016), morphology and pollination (Ørgaard & Jacobsen, 1998), cytology (Jacobsen, 1977a;arends et al, 1982), geographical distribution and habitat ecology via flora contributions (ipor et al, 2009;Jacobsen, 1985Jacobsen, , 1987li & Jacobsen, 2010;Jacobsen et al, 2012;othman et al, 2009), and molecular studies (othman, 1997;othman et al, 2009;ipor et al, 2010;Jacobsen et al, 2015a;rosazlina et al, 2015, rosazlina 2016rosazlina et al2017). We have undertaken a largescale hybridization programme, resulting in the production of more than 80 interspecific F 1 generations of which only a few have yet been published (ipor et al, 2015;Jacobsen, 1977bJacobsen, , 1981arosazlina, 2016;rosazlina et al 2017).…”

“…Chromosome numbers within the genus vary (Jacobsen 1977a;arends et al, 1982): 2n = 36, 72; di-and tetraploids (2n = 54, triploids have also been recorded): the C. thwaitesii schott group from sri lanka, the C. crispatula group, and two additional species from Borneo. 3n = 34, 68, 102; di-, tetra-and hexaploids (2n = 51 and 85, triploids and pentaploids have also been recorded), with many species from the Malesian region.…”

Cytotaxonomy and evolution in Cryptocoryne (Araceae)

“…In the literature the following diploid numbers have been mentioned: 20, 22, 28, 30, 33, 34, 36, 42, 54, 60, 66, 68, 72, 85, 88, 90, 102 and 132 (Jacobsen, 197620, 22, 28, 30, 33, 34, 36, 42, 54, 60, 66, 68, 72, 85, 88, 90, 102 and 132 (Jacobsen, , 1977a20, 22, 28, 30, 33, 34, 36, 42, 54, 60, 66, 68, 72, 85, 88, 90, 102 and 132 (Jacobsen, , 197920, 22, 28, 30, 33, 34, 36, 42, 54, 60, 66, 68, 72, 85, 88, 90, 102 and 132 (Jacobsen, , 1980Arends et al, 1982;De Wit, 1983). Some of these numbers (viz.…”

“…x = 10, 11, 14, 15, 17 and 18 (Jacobsen, 1977a;Arends et al, 1982; see Table 1). It has been proposed (Arends et al, 1982) that this series of base numbers originated as an aneuploid series, starting at x = 18 and decreasing to x = 10.…”

“…x = 10, 11, 14, 15, 17 and 18 (Jacobsen, 1977a;Arends et al, 1982; see Table 1). It has been proposed (Arends et al, 1982) that this series of base numbers originated as an aneuploid series, starting at x = 18 and decreasing to x = 10. This suggestion is based on the assumption that x = 18 is the most primitive chromosome condition, which seems to be confirmed by the fact that the closely related genus Lagenandra has 2n = 36, x ---18 in all known species (Arends & Van der Laan, 1978).…”