B-Cromosomi Nel Genere Urginea (Liliaceae)

Abstract

B- Chromosomes in the genus URGINEA (liliaceae). — The karyotype of a plant of Urginea fugax var. major coming from Morocco has been investigated cytologically and found to be diploid with a chromosome complement of z (zygotic number) = 2n = 20 + 6B's.

This karyotype can be expressed by the following formula: z = 2n = 20 + 6 B's = 2L ₁ + 2L ₂ + 2M ₁ + 2M _n3 + 2M _n3 + 2M ₄ + 2M ₅ + 2M ₆ = 2M ₇ + 2M ₈ + 6B's (= 2S ₁ + 2S₂ + 2S₃).

From a comparative study of this karyotype and karyotypes of other species of the Genus Urginea the same chromosome complement of 2n = 20 (= 2L ₁ + 2L ₂ + ….2M ₈ ) was found to exist in Urginea fugax var. major and var. typica, U. maritima, U. undulata and U. maura (U. aurantiaca shows the pair 2M ₄ bis in place of 2M ₅).

The cytological literature on the Genus Urginea has been reviewed and the occurrence of B- chromosomes recognized for the following species:

U. fugax (var. typica and var. major): Martinoli, 1949; Battaglia, 1957 b and the present paper;

U. aurantiaca: Battaglia, 1958;

U. indica: Raghavan and Venkatasubban, 1940;

U. epigea: De Wet, 1957;

U. lydenburgensis: De Wet, 1957;

U. rubella: De Wet, 1957.