Alex Summers, Glasshouse Supervisor
Cambridge University Botanic Garden
Of all the questions to be asked, the most common and also the most difficult is: what is your favourite plant in the collection? As the Glasshouse Supervisor I look after plants that originate from tropical, Mediterranean and desert biomes. These come in all shapes and forms and usually have a great back-story – either a unique quirk in their biology, or an interesting cultural use. However, at this very moment, one stands out from the rest: the Sacred Lotus, Nelumbo nucifera.
Nelumbo nucifera originates from tropical Asia and is distributed from Iran through to northeast Australia. Its association with human culture goes back at least 3000 years and it gets its common name, the Sacred Lotus, from its importance in many religions and cultures. In Hinduism it is often used as an example of divine beauty and can be found depicted throughout Hindu iconography. In Buddhism and Confucianism it represents purity, due to its delicate flowers, which arise from the muddy depths of pools and slow-moving waterways.
Its biology is as fascinating as its cultural significance. It is an aquatic perennial, with growth arising from sausage-like rhizomes (subterranean stems). The internal structure of these rhizomes, which look like a cart wheel when seen in cross-section, allows the plant to move oxygen and carbon dioxide between leaf and root. The flowers are equally interesting, able to hold their temperature above that of the surrounding environment in order to attract cold-blooded pollinators. Perhaps the most impressive aspect of their biology, however, is the super-hydrophobic leaf surfaces which mean that even the stickiest substances are unable to remain on its leaves. This phenomenon is the result of a unique surface microstructure and is currently the subject of research by engineers developing selfcleaning materials.
The Sacred Lotus is a true wonder of the plant world, and if I have not yet convinced you of that, I have one last remarkable fact. A seed taken from a lake-bed in Manchuria (China), and determined to be 1288 years old, was germinated in 1995. In my eyes, this plant truly deserves to be revered.