What is the characteristic feature of the species under the genus Rudbeckia?

The genus Rudbeckia is well-known for its striking and vibrant yellow flowers, which is one of the most characteristic features of these plants. This genus includes species such as Rudbeckia hirta, commonly known as black-eyed Susan, which prominently displays yellow petals surrounding a dark center. The bright yellow color not only makes them popular in ornamental gardening but also attracts various pollinators, including bees and butterflies.

While some species may exhibit variations in color, the predominant feature of yellow flowers is widely recognized and serves as a defining trait of the genus. This characteristic contributes to their popularity in landscaping, particularly in sunny garden beds where their bold color can create a stunning visual impact.

Other aspects such as drought tolerance can vary among species within the genus, and while they are generally adaptable, it's not exclusive to Rudbeckia that they are known primarily for this trait. Likewise, their preference for full sun as opposed to shade and their non-aquatic nature further reinforces the significance of their yellow flowers as the hallmark of the genus.