The fruit of the elm tree is known as a samara.
Understanding Elm Tree Fruits: The Samara
Elm trees, including notable species like the American Elm (Ulmus americana), produce distinctive fruits called samaras. These specialized fruits play a crucial role in the tree's reproductive cycle, particularly in seed dispersal.
Key Characteristics of Elm Samaras:
Elm samaras possess several unique features that distinguish them:
- Shape and Size: They are typically small, oval, and notably flat.
- Structure: Each samara is a dry, papery fruit. A defining characteristic is the presence of a distinctive notch at its edge.
- Texture: They often have tiny hairs at the edge of the papery fruit, contributing to their aerodynamic properties.
- Development: These fruits develop from the tree's perfect flowers, which contain both male and female reproductive parts.
- Maturation: Elm samaras mature and detach from the tree relatively quickly, often abscising (falling off) soon after maturation in mid-spring. This early maturation allows for efficient wind dispersal before the full canopy of leaves develops, which could obstruct their spread.
Role in Seed Dispersal
The unique flat and papery structure of the samara is an adaptation for wind dispersal. When they fall from the tree, their design allows them to helicopter or glide on air currents, carrying the single seed they contain further away from the parent tree. This mechanism helps reduce competition between parent and offspring, promoting wider distribution and colonization of new areas. This type of fruit is common among various tree species, not just elms, including maples and ashes, all utilizing wind as a primary means of seed dispersal.
Fascinating Facts About Samaras
- "Helicopter Seeds": Due to their spinning motion as they fall, samaras are often colloquially referred to as "helicopter seeds" or "whirlybirds."
- Rapid Maturation: The quick development and abscission of elm samaras in spring differentiate them from many other tree fruits that mature later in the summer or fall.
