Illustration of a pollen grain of a willow tree (Salix sp.). Each grain has an elongated form with rounded ends and a grooved and pitted surface. The willow tree flowers early in the year before its leaves appear. The pollen is a strong allergen and can cause allergic reactions such as rhinitis and hay fever, with some people developing asthma-like symptoms. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Michael Alexowski |
Bildgröße: | 2480 px × 3507 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |