Presence of Senecio sylvaticus L. (Asteraceae) in Turkey

The annual plant Senecio sylvaticus L. (Asteraceae) is regarded as a doubtfully recorded in Turkey. It has not been collected in the country since the first report of its occurrence in the north eastern Black Sea Region in 1875. This paper reconfirms the occurrence of Senecio sylvaticus in Turkey. New specimens were collected from the Ereğli and Alaplı regions (Zonguldak province, NW Turkey) in 2014. The species description, distribution maps and photographs are given.

Comparative response of closely related species to reduced competition. I. Senecio sylvaticus and S. viscosus

A comparison of the reproductive and vegetative responses of Senecio sylvaticus and Senecio viscosus to the time and intensity of reduced competition is reported. The two species reacted similarly to thinning in terms of (1) reduced seed production per experimental population and increased seed production per individual, (2) reduced head production, (3) reduced vegetative dry weight, and (4) increased plant height.The two species of Senecio differed in their reaction to thinning in terms of (1) initial anthesis, (2) number of seeds per head, and (3) mortality. Thinning had no significant effect in altering the initial flowering of S. sylvaticus. Early thinning in S. viscosus advanced the flowering date while late thinning delayed flowering. S. sylvaticus was capable of increasing the number of seeds per head only if thinning occurred early, whereas the number of seeds per head in S. viscosus significantly increased at all thinning periods. Lastly, S. sylvaticus experienced much heavier mortality than S. viscosus.