What leaf and flower features help identify plants in the genus Clethra?

Plants in the genus Clethra (family Clethraceae) are woody trees or shrubs that can be identified by the following leaf and flower characteristics:

Leaf Features

• Arrangement: The leaves are arranged in a spiral pattern along the stems and often tend to be clustered at the ends of the branches.12
• Appearance: The leaves are typically toothed and can be either deciduous or persistent (evergreen).31

Flower Features

• Inflorescence: The flowers are arranged in racemose inflorescences (racemes) located at the ends of the branchlets.2
• Appearance: The flowers are generally small and fragrant, often described as handsome spikes.312
• Structure: The flowers possess sepals and petals that are either free or only basally fused. A notable diagnostic feature is the presence of 10 stamens that feature distinctive arrow-shaped anthers, which open by pores.2
• Fruit: The resulting fruit is a capsule divided into three compartments (locules).42

Additionally, these plants often exhibit stellate pubescence (star-shaped hairs) on their vegetative structures.4