Bizarre Botany II

Credit: Carolyn Jones

Following up on the interest in our original Bizarre Botany piece, here are 10 more weird and wonderful plants (and bugs!) from around the world

To many humans, plants are pretty or tasty or useful – but otherwise seemingly tame or even boring. But ask a botanist what secrets lurk within those innocent-looking leaves, and you might be in for a surprise!

Poplar leaves (Image: Flickr / Alan Levine)
 

1. UN-POPLAR IDEA

Since plants can’t run away from their enemies, they have evolved other defense mechanisms to keep foes at bay. Many plants, such as common poplar trees (Populus), produce chemicals that deter animals that eat their leaves.

For example, poplars produce chemicals that bind with a leaf-munching herbivore’s digestive enzymes, inactivating them. The effects range from indigestion to serious illness. If there are other plants to eat, the grazer usually moves on to the next item on the menu.

What is remarkable is that these anti-grazing chemicals aren’t produced by the plant at all times. A poplar leaf can detect when it is being eaten, and it jumps into action. The genes that make the nasty chemicals are switched on and direct the cells’ machinery to commence deterrent production. Botanists have even shown that plants can differentiate between physical damage and grazing – even to the extent of detecting moose saliva!

Stinging nettle (Image: Flickr / Leslie Seaton)

2. THE STING

To deter mammalian grazers, some plants – such as stinging nettle (Urtica dioica) coat their leaves with stinging hairs. If brushed against, the brittle tip of the hair breaks off, leaving a beveled point that can penetrate the mammal’s skin. This little “syringe” comes loaded with ingredients that cause skin pain and itchiness – an event with which I’ve had personal experience while hiking.

Stinging nettle plants have the ability to ramp up production of these irritating hairs – plants in a heavily grazed field have more hairs per unit of leaves area than plants growing out of the reach of herbivores. Interestingly, slugs and snails escape harm by gently pressing the hairs over before feasting on the nettle’s leaves.

Braconid wasp (Image: Flickr / Gilles Gonthier)

3. BAD CHEMISTRY

If an aphid lands on a plant and starts sucking out the plant’s juices, the plant has no way to shake or hit it off. Never mind! The plant can emit a chemical that attracts the aphids’ enemies: parasitic wasps.

The wasp flies in and attacks the aphid by laying an egg inside it. When the wasp’s larvae hatches, it in turn eats the aphid. Presto – job done, without lifting a finger. There are many examples of this three-tiered feeding system in the plant world, and botanists are discovering more each day.

Fungi and pandanus plant. The gardener observed these fungi grow overnight and are gone by the time the day gets hot. (Image: Flickr / Peter Wright)

4. AT THE ROOT

Ninety percent of the world’s plants have a beneficial relationship with fungi that inhabit their roots. The fungi get a little protection from the elements by huddling up to the roots, but their main gain is a share of the plant’s carbohydrates (produced by photosynthesis) and the essential building block phosphorus.

The fungi help the plant by increasing its ability to absorb water and certain nutrients from the air and soil. This is especially important where plants are growing in poor soils – such as the rocky soils found in British Columbia’s forests. The fungi that live like this are called mycorrhizal fungi (myo=fungus + rhizo=root).

The next time you plant legumes (peas and beans) buy a little packet of soil inoculant and treat your seedlings to their own mycorrhizal helpers.

Nut on a ginkgo biloba tree (Image: Flickr / solylunafamilia)

5. REPRODUCING SWIMMINGLY

Just like animals, plants produce eggs with a half-set of genes and sperms with a complementary half-set of genes. United, they form a new plant that grows and matures on its own.
Unlike animals, the sperm of flowering plants and conifers are not motile. That is, they do not propel themselves using a whip-like flagellum. They move toward the egg in a pollen tube, a good adaptation for life on dry land.

However, two common ornamental plants – cycads and ginkgo trees – have motile sperm. This attribute is a reminder that their ancestors evolved well before flowering plants and conifers – in fact, 270 million years ago!

Ginkgo trees make wonderful garden plants, and cycads thrive indoors in a bright location. Their quirky reproductive structures have served them well for eons.

Castor bean plant (Image: Flickr / Ray Tibbits)

6. SPY STORY

The castor bean plant (Ricinus communis) is a dramatic, large-leaved annual plant used to create a tropical ambience or as a focal point for bedding schemes. Especially handsome are the red-leaved cultivars – you may have seen them at your local park.

This plant’s beans are used to make castor oil, but the waste mash – which is produced in the thousands of tones annually – contains the deadly poison ricin. Only 1.8 mg (about 1/228^th the size of an aspirin) inhaled or injected will kill most adults. Ricin is a protein that enters into human cells and “jams up” the ribosomes – the little machines that crank out our proteins. And since the proteins are the workhorses of our bodies, death soon follows.

The most notorious incident involving this plant poison occurred in 1978 when a Bulgarian dissident living in London was shot with a weapon disguised as an umbrella. The ricin-containing pellet that entered Georgi Markov’s skin was discovered during his autopsy. Russian agents have since admitted that the pellet was supplied to the Bulgarian secret service by the KGB.

Strychnos axillaris (Image: Flickr / Ian Sutton)

7.  POISON TIP

The genus Strychnos contains almost 200 species of beautiful tropical trees, shrubs and vines – several of which produce the neurotoxin strychnine.

How does it affect humans? Our nervous systems produce two types of signals: excitatory signals stimulate action and inhibitory signals quiet action. The fine balance of these signals creates smooth movements with appropriate responses. Strychnine halts the inhibitory signals in the spinal cord and brain stem, so poisoning victims experience hyperexcitability: convulsions, spastic contractions of skeletal muscles, and ultimately death due to an inability to breathe.

South American hunters have taken advantage of the neurotoxin in Strychnos toxifera, using it as arrow-tip poison to immobilize their prey.

Chondrodendron tomentosum comes from the Menispermaceae family (Image: Wikimedia Commons / Franz Eugen Köhler )
 

8. NO CONTRACT

Another arrow-tip poison, curare, comes from the tropical South America vine Chondrodendron tomentosum. Curare works at the neuro-muscular junction, where it prevents the “contract now” messages from reaching the muscles. This results in the opposite effect as strychnine: no contraction of the muscles that control breathing means death by asphyxiation.

Curare was introduced into the operating room in 1942 to target the relaxation of muscles affected by the surgery. This allowed the use of lighter doses of anesthetics and fewer complications following surgery.

In these last two examples, it’s hard to tell which is more bizarre – the plant or the people that are looking at them and using their imaginations!

Swamp cypress in VanDusen Botanical Gardens in Vancouver. (Image: Cindy Sayre)

9. TREE’S KNEES

10. LADY IN THE BATH

Long-cultivated in Japan, Dicentra spectabilis was introduced to Europe in 1846. I like to imagine that this bizarre observation was dreamt up on a lazy afternoon, over tea, in a pretty garden in England.

Pick one of the lovely, pendant flowers of bleeding heart and invert it. Gently pull it open and you’ll see what’s been called “the lady in the bath.” Do you fancy that she looks a bit shocked at being disturbed?