Carnivorous Plants: Sarracenia

COOL Science Blog

Carnivorous Plants: Sarracenia

Enjoy the Beauty

Watching any plant grow is fun and interesting science, whether you’ve nurtured it from a seed or a young plant; starting with a full grown plant is even easier and it’s fascinating to observe the seasonal changes.

At COOL Science we’re fortunate to be able to grow some types of carnivorous plants on a sunny windowsill. These are really fascinating and unusual plants and we’re especially excited over the beautiful flower our Sarracenia cultivar ‘Tygo’ has produced this year.

Sarracenia Tygo Flower from side
Sarracenia Tygo Flower from top

Beware the Trap!

Sarracenia or ‘trumpet-pitchers’ as they are commonly known trap their ‘prey’ by means of tall slender tubes or pitchers at the top of which is a wing-like 'hood'. The pitcher is covered with nectar-producing glands, especially abundant at the base of the hood; the nectar is quite strongly sweet-smelling and is certainly attractive to flies!

Once on the pitcher, if the fly enters the mouth and goes into the tube, downward pointing hairs on the inner walls of the tube may be enough to prevent the fly back-tracking, it may be able to fly out but could be restricted by the lack of space. After the hairy-section of tube there is often a slippery, waxy-walled section which means the fly cannot gain a foot-hold and falls to the base of the pitcher.

This time longer downward pointing hairs do prevent the fly going back up the tube and juices which contain acids and enzymes are secreted by glands in the lower parts of the pitcher, it is here the fly is digested. The cells lining the base of the pitcher have no cuticle so the nutrient rich solution diffuses straight into the sap and is then in the plants system.

Sarracenia Pitchers
Sarracenia Seed and Pitcher hood showing nectar globules

Marvel at the Complexity!

Although most famous for their pitchers, which in some species can be very large, Sarracenia also produce flowers. The flower starts off as a little round bud on a short stump which gradually gets longer and longer, until its a slender stem. The bud grows and opens into the long petalled flower which can have quite a strong scent too, although it’s not particularly pleasant!

The style of the flower is shaped like an upside down umbrella with five points, each having a stigma. The ripe pollen is caught in this umbrella when it falls from the anthers and will be picked up by visiting insects such as bees. When the bee visits another Sarracenia flower the pollen may be deposited on one of the five stigmas around the points of the style on its way to the inner part of the umbrella. Incidentally, self-pollination is prevented because the bee has to go under a petal to get out of the umbrella and so does not touch the stigma.

The petals fall after a few weeks and the rest of the flower begins to dry up, staying on the stem a surprisingly long time! If it has been pollinated successfully the ovary will swell and sometimes get a bumpy texture on its surface. Sarracenia seed can take up to 5 months to mature; but eventually the seed-pod dries up and turns brown, then it splits and the seeds are dispersed. We were lucky enough to get some seed from another Sarracenia last year, they have been planted but nothing has grown… yet!

Diagram of a cross-section of Sarracenia Flower

Further Information

Carnivorous plants may seem like they would be very difficult plants to grow, but some are actually quite easy to grow and require little maintenance. They do however have very specific needs in the way of growing medium, water and light and some will only grow in heated greenhouses; as with all plants, some research on their specific requirements goes a long way!

If you can get hold of them, there are two invaluable books which were written by Adrian Slack (1933-2018) who was an absolute authority on carnivorous plants! There are even two plants named after him; Drosera slackii (a sundew) and Sarracenia 'Adrian Slack'

  • Carnivorous Plants (first published 1979) imparts an indepth knowledge of these plants, along with lots of photographs and drawings.
  • Insect-Eating Plants and How to Grow Them (first published 1986) is fantastic if want to grow carnivorous plants with all sorts of useful information on how to provide a suitable environment and care for your plants.

The International Carnivorous Plant Society (ICPS) shares knowledge and news of carnivorous plants to members via it’s Carnivorous Plant Newsletter; there is also a wealth of information available to everyone via it's website.

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