The Plant of the Week, this week, is the Sacred Lotus which I’ll admit, from a distance, looks like a tropical water lily. It’s not a water lily, nor is it tropical.

Nelumbo nucifera — GBIF occurrences

Data: GBIF · Map: © OpenStreetMap contributors

This might surprise a lot of readers, particularly if you live in Sri Lanka, Indonesia or northern Australia. However, Plants of the World Online lists Nelumbo nucifera as native in Ukraine and Khabarovsk in Russia to the north east of China. Cultivation has taken it much further, and it’s now established as in distant countries around the world. What it wants is slow moving water, so it’s often found in ponds and lakes. A mass of rhizomes sit in the mud in the pond bed, and from here stalks reach up to two metres to break the surface.

A tropical garden pond. On the left, a stand of lotus with round blue-green leaves held on upright stalks above the water, and a single pale cream flower open among them. On the right, true water lilies of a different species, their mottled reddish-green pads lying flat on the dark water surface with pale flowers sitting at water level between them. Beyond the pond, a fan palm, dense green scrub and a larger lake under a blue sky with scattered cloud.
Nelumbo nucifera in USA by borisdefosse CC BY-SA via Pl@ntNet

The leaves might have the round look of lily pads, but hey don’t lie flat, floating on the water. Instead a stalk, or petiole, hold them well above it. Also, unlike water lilies, there’s no notch where the stalk connects to the pad. The leaves look almost supernaturally clean, because the surface is hydrophobic. Water beads and rolls off, taking muck with it. But it’s not just the leaves that are odd. There’s the flowers too.

A wide lotus swamp in flower, with a large pale pink flower open in the foreground. Its petals shade from deep pink at the tips to cream at the base, framing a flat-topped yellow receptacle pitted with small holes, each containing a developing seed, and ringed by a dense fringe of yellow stamens. Behind it, dozens more flowers at different stages — tight pointed buds, part-open cups, and fully open blooms — stand on stalks above round green leaves reaching to the horizon. Coarse grasses grow along the near bank; a low treeline and thin smoke lie in the distance.
Nelumbo nucifera in Cambodia by hélène thomas CC BY-SA via Pl@ntNet

The flowers have a trick of opening gradually to make sure they’re crossing their pollen with other plants. The pink to cream flowers open slightly at first, so pollinators can enter at the top, bringing in pollen from other plants. But they can’t access the flower’s own stamens on the first day it opens. Overnight visitors are trapped within the flower. It’s not till the second day when the flower opens wider that the stamens are released, allowing the plant to release pollen and pollinators to travel elsewhere.

A lotus flower photographed from above, fully open. Broad petals, pink at the tips and white towards the centre with fine darker pink veining, are spread flat. At the centre sits a domed yellow receptacle like a flat-topped shower head, its surface pitted with around thirty holes, each holding a developing seed with a small dark stigma at its mouth. A ring of stamens surrounds the receptacle: the inner ones pale and standing upright, the outer ones splayed outwards and tipped with yellow anthers that have opened to shed pollen. Behind the flower, large green lotus leaves and dark water.
Nelumbo nucifera in China by Eine süße Katze CC BY

The pollinators that the flowers evolved for were probably beetles, though bees and flies visit the plants in some places. One of the ways the flower attracts beetles and others is that it can regulate its heat. Even on a cold 10 degree day, the flower can raise its temperature to between 30 and 35 degrees centigrade. Exactly why it does this is unclear. The heat could help spread its perfume, boosting its appeal to pollinators. Or it could be that the heat itself is a reward, providing energy to beetles as they shelter in the flower overnight.

A pale pink lotus flower in a partly open state, photographed from the side against a background of large green lotus leaves. The outer petals have opened and bent back or fallen away, while the inner petals remain furled into a closed cup, hiding the centre of the flower entirely. The petals are white towards the base, deepening to pink at the tips, with fine longitudinal veining. The flower is held on a smooth green stalk rising clear of the leaves below.
Nelumbo nucifera in Russia by Repina Tatyana CC BY

The puzzling thing is that the plant doesn’t just heat the flowers. It regulates the heat. Seymour and Schultze–Motel report that when daytime temperatures get to 45 degrees, the flower is still in the 30 - 35 range.

A dried lotus seed head, photographed close up against blurred green leaves. The woody, brown, roughly circular receptacle is pitted with about twenty deep cavities arranged in a honeycomb, each opening rounded and separated by thick ridged walls. Most cavities hold a single smooth grey-brown nut sitting loose at the bottom, each with a small dark point at its tip; several cavities are empty. A second, similar seed head is out of focus behind.
Nelumbo nucifera in Japan by WATANABE Hitoshi 渡辺仁 / iNaturalist CC BY

Once pollinated the plant produces seeds, known as lotus nuts, and these are something special too. The seeds turn the plant into a time-traveller. A study of the seeds shows that they could be 1,300 years old, and still germinate into a new plant. That means a seed dropped around the time of Charlemagne could still sprout tomorrow.

Nelumbo nucifera — observations by month

Worldwide · n = 7,038

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Data: iNaturalist verifiable observations.

iNaturalist is going through a peak of observations at the moment, which suggests it’s flowering time for many observers. Keep an eye out for the nuts. If you can collect a few, you have something to pass on to your great(×50) grandchildren.

Cover image: Nelumbo nucifera in India by Noopur🍀 / iNaturalist CC BY-NC