WHAT SHOULD WE LOOK FOR?
This can get a bit tricky in cases where the male and female flowers look nothing alike. But the culms of the same species are always identical so we look at the culm.
What do we look for on the culm? First of all, we should note whether the culm is branched or unbranched. This is a very important clue to identifying the species. Then we look for nodes or joints along the culm. These appear as dark rings at regular intervals along the length of the culm. There may be a brown leaf-like structure at these dark rings. They are known as sheaths and are all that remain of the leaves that would have grown out of this point in times past. These sheaths may either remain on the adult plant (these are known as “persistent”) or drop off, an important clue to what species we are looking at.
Lastly, we look at the flowers at the top of the culm. Different restios flower at different times of the year, and it may be difficult to identify them when they are not flowering.
As mentioned before, the male and female flowers occur on separate plants and the male and female flowers often look very different. The individual restio flowers are very small and they are borne in a cluster called the inflorescence. The flowers may be completely obscured by gold or brown leaf-like structures (called spathes) – in this case, one only becomes aware that they are flowering when the anthers of the males or the styles of the females are prominently displayed to facilitate pollination.
The male anthers appear yellow and boat-like, filled with minute grains of pollen, when viewed under a loupe (magnifying lens), while the female styles are often brightly coloured and feathery to better catch the pollen. Flowers grow on little stalks called pedicels that either stick upward or hang down (pendulous). Pendulous flowers are invariably male.
Male restio flowers produce pollen and female flowers, after pollination, produce seeds. Restios use the simple method of wind-pollination. The male flowers produce copious pollen on their boat-shaped anthers where the pollen rests until there is enough wind to blow it to possibly distant female flowers. Shake or knock a flowering male restio and you will see the pollen flying.
Interestingly, restios don’t hybridise – pollen grains of the different species have unique shapes and chemical signals so that they will only be accepted by the style of a female flower of the same species.
Restio seeds come in the form of little nuts or as seeds in a capsule. Like all other plants, restios need to spread their seeds. Some seeds have tasty appendages (called elaiosomes) that ants like to eat, so the ants carry them to their underground nests where seeds are stored ready to germinate when conditions are right. Some restio seeds are large and much too heavy for ants. The mystery of how they are dispersed was solved when scientists recently observed that they look and smell like antelope droppings and can ‘fool’ dung beetles into rolling them away and burying them.
Restios are well adapted to fire. Many of them simply sprout again from the roots. Others will grow from seeds buried by the ants that germinate in response to the smoke and heat of a fire. The thatching industry relies on the remarkable ability of restios to rapidly grow after being harvested.
The most common restio in Fernkloof is the genus Restio. This is a bit confusing as restio is also the common name for all the Restionaceae. The members of the Restio genus all have branched culms and sheaths that stay on the culms at the nodes – i.e. they are persistent. But that is really all they have in common with each other. Members of the genus Restio vary enormously in appearance and the best way to get to know them is to choose one or two that you fancy and remember their names and their distinguishing features.
Another prominent genus is Thamnochortus. In this genus, the males and females look quite different and raise some smiles. The female flowers stand proud, while the males are droopy. The culms are unbranched and the sheaths are persistent. A closely related genus of Thamnochortus is Staberoha; they often attract attention because they are showy – the male flowers look like drooping rusty balls and the females are upright and skinny.
Like Thamnochortus and Staberoha, members of the genus Hypodiscus are unbranched and their sheaths are persistent. The flowers, however, are round and prickly, giving them their nickname ‘Hedgehogs’. Males and females are generally fairly similar, with the males a little beer-bellied and the females slim and elegant. The exception is the ‘Silver Hedgehog’ Hypodiscus argenteus with flashy, silvery male flowers and females with bright feather-boa styles.
Possibly the most elegant genus is Elegia. Its members are unbranched and the sheaths drop off the culms. There are two types of Elegias – the blonde Elegias and the dark Elegias. One can’t miss the blondes – they have very pretty golden spathes protecting the flowers. The male spathes are a bit ‘looser’ in appearance, exposing the flowers. However, the dark Elegias are quite different. They have few spathes and small dark flowers like millet seeds, arranged in a spiral at the end of the culm. In young plants the sheaths have not yet dropped off and form dark rings around the culm, making them look like porcupine quills. The male and female flowers of the ‘dark’ Elegias are almost identical, the females just a little ‘chubbier’. One could be excused for thinking the blonde and dark Elegias are not closely related – they were in fact in different genera until their DNA was analysed.
Easy Aide Memoire for Restio ID
sheaths dropping off
|Group (Genus)||Restio||Thamnochortus, Staberoha, Hypodiscus||Elegia|
Remember there are always exceptions to the rules.
Dr Anina Lee : Whale Coast Conservation
Illustrations of some of these restios can be found in the colour brochure:
- Favourite Restios of Fernkloof Nature Reserve published by the Hermanus Botanical Society.
- Recommended reading: Restios of the Fynbos by Els Dorrat-Haaksma and H. Peter Linder