Lesley, J. W. and Margaret M. Lesley
A single plant occurred among six R2 plants from seed treatment with P^32 in the variety Canary Export. It was conspicuous by the smaller size of the trichomes and glandular hairs. The trichomes are smaller and are crooked and distorted. Multiple curvature is common. Singed behaves as a simple recessive. It resembles hl hairless (Butler, L. 1952. Jour. Heredity 43: 25-35) but two F1 families of 8 and 6 plants from crosses of hl with different singed pollen parents were all normal. Singed and hl apparently have different loci. In some F1 singed x normal p.m.c., chromosomal irregularities were observed. The hl tester plants at Riverside (Butler's Acc. 184) were distinctly unfruitful. This applies to some singed plants in F1 and F2 compared with non-singed sibs. F2 linkage tests indicate that singed is not closely linked with c, a; y, l or d. As a rule in F2 less than 25% of F2 plants are singed. The symbol sn is suggested for this mutant.