Variety traits

Double-flowering in Rudbeckia hirta L.

Rudbeckia hirta L.

Double-flowering in Rudbeckia hirta L. is a breeding trait manifested by an increase in the number of ray florets at the expense of the central disk florets.

In the reference 6 varieties crop Black-eyed Susan, where this is mentioned in the description.

The wild form of Rudbeckia hirta is single-flowered and consists of a capitulum with a single row of ray florets. In breeding practice, double-flowering is classified into three categories: single, semi-double, and double, with the latter characterized by the central disk being almost completely replaced by additional rows of ray florets.

Quantitative assessment of the trait is not standardized and remains descriptive within variety specifications. Double-flowered forms often exhibit reduced fertility due to a deficiency of viable pollen, which limits their utility for pollinating insects. The degree of trait expression may vary depending on the growing conditions of the hybrids.

General information about the subject — on the page Double flowering / Reversion.

Sources8

Varieties of Black-eyed Susan mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.