Letter | Published:

Chromosome Number of Rorippa (Nasturtium) sylvestris

Nature volume 158, page 666 (09 November 1946) | Download Citation



THE only published count of the chromosome number of Rorippa sylvestris (L.) Besser (= Nasturtium sylvestre (L.)R.Br.) appears to be that of Manton1, who found 2n = 32. In a search for the other parent species which, with Nasturtium officinale, has given rise to the allotetraploid species N. uniseriatum2, I studied a specimen of R. sylvestris obtained from the Newry canal at Newry (border of Co. Down and Co. Armagh, N. Ireland) and found this plant to have a chromosome number of n = 24 and 2n = 48. Similarly, specimens of R. sylvestris from Horton-in-Ribblesdale (Yorkshire) and from the Botanic Gardens at Cambridge and Kew (the plant was growing as a weed in both gardens) were all found to have a chromosome number of n = 24. There thus seems no doubt that British specimens of R. sylvestris have a chromosome number of 2n = 48 and not 2n = 32 as reported by Manton.

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  1. 1.

    , Ann. Bot., 46, 509 (1932).

  2. 2.

    , and , Ann. Bot., n.s. 10, 1 (1946).

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  1. Plant Breeding Institute, School of Agriculture, Cambridge. Oct. 12.

    • H. W. HOWARD


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