Herbaceous Plants with Bulbs

By Staff
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Enter the world of botany with a quick overview that sheds some light on herbaceous plants with bulbs.

August 2018
By Katie Scott and Kathy Willis

Cover courtesy of Templar Company Limited

Botanicum (Big Picture Press, 2017) by Katie Scott and Kathy Willis is a scientific and artistic introduction to the world of botany. With vivid illustrations by Scott and descriptive text by Willis, a professor of Biodiversity at the University of Oxford and director of science at the Royal Botanic Gardens, the botanical guide is both educational and enjoyable. Scott is also the illustrator to a sister book,Animalium. The following excerpt discusses bulbs.

If you cut open an onion, you will see many different layers of fleshy material and, right in the middle, a pointed shoot. The outer layer is encased by a thin, paper-like skin. At the base are small, stringy roots. It is a tightly wrapped food parcel, a way of ensuring that the plant survives from one year to the next during periods of drought or cold.

The onion is a bulb. A bulb is an underground shoot surrounded by modified leaves (the layers). It will only grow if it is pointing upward in the ground. When the weather gets bad, the plant effectively goes into a kind of hibernation, or dormancy. The part of the plant sticking up above the ground dies. When the weather warms up or the rains arrive, the shoot grows through the bulb, up through the soil, and out of the earth. The first snowdrops, bluebells, crocuses, and daffodils poking their heads above ground are a familiar sign of spring in temperate regions, and these shoots are soon followed by their abundant flowers.

But even though these plants produce bulbs (and can often survive for years in this form), they still reproduce with seeds. Seeds develop from the fertilized flowers and are dispersed in the usual variety of ways. This is a slow process— it takes up to five years for a mature daffodil plant to develop from a seed because in the first few years, the plant puts most of its energy into growing the bulb.

Plants with fleshy underground parts have been used for food and flavoring for thousands of years. Archaeological evidence indicates that onions, for example, were cultivated in ancient Egypt. Garlic is another bulb that has a long history in food and medicine: 1,500-year-old garlic bulbs were found in the tomb of the Egyptian pharaoh Tutankhamun, and garlic is mentioned in the Bible, the Qur’an, and in many ancient Egyptian, Greek, Indian, and Chinese texts.

Another bulbous plant with a long history in human food is the crocus. In this case, however, it is not the bulb but the pollen-bearing threads called stigmas that are used. These reddish-orange threads are potent and valuable both as a spice for cooking and as a powerful dye for clothes and are more commonly known as saffron. Pound for pound, saffron is the most expensive traded foodstuff in the world.The ancients appreciated its value: the Minoans of Crete grew and traded saffron from around 1550 bce.

Rather more common, but equally precious in their way, are the humble daffodil and tulip. The tulip has an unwelcome claim to fame. It was the source of the world’s first financial crash in Holland in the 1630s. At this time, individual bulbs were traded for the price of four oxen, eight pigs, twelve sheep or a thousand pounds of cheese.

Illustration by Katie Scott

Key to plate

1: Saffron crocus

Crocus sativus

Height: 3–7 inches/8–15 centimeters

Vertical cross section through capsule showing developing seeds

Stamen, consisting of filament and anther (c) Stigmas (d) Entire plant

2: Garlic

Allium sativum

Height: 12–16 inches/

30–45 centimeters

(a) Stem and bud (b) Flower

Cross section through bulb

(d)Bulb and stem

3: Tulip

Tulipa sp.

Height: 6–30 inches/

15–75 centimeters

4: Red Onion

Allium sativum

Height: 12–16 inches/

30–45 centimeters

(a) Stem and bud (b) Flower

Cross section through bulb

More from Botanicum:

BOTANICUM. Text copyright © 2016 by Kathy Willis. Design copyright © 2016 by The Templar Company Limited. Illustrations copyright © 2016 by Katie Scott. Reproduced by permission of the publisher, Candlewick Press, Somerville, MA.

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