Carnivorous Plants

PITCHERPLANT

Sarracenia purpurea

Pitcherplant Family [Sarraceniaceae]

month8jun month8june month8jul month8july

status
statusZneophyte
 
flower
flower8red
 
flower
flower8orange
 
flower
flower8beetroot
 
inner
inner8green
 
morph
morph8actino
 
petals
petalsZ5
 
type
typeZtubular
 
stem
stem8round
 
smell
smell8sweet
sweet
sex
sexZbisexual
 

5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
The flowers are those nodding (drroping downwards) solitary things looking like street lights and are much higher than the pitchers at their feet.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
Flowers on long leafless stalks and stand about 60cm high. They have 5 purple sepals and 5 purple petals. The pitchers surrounding the stems near ground-level are hollow tubes with a large banner atop.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
Some pitchers are red to purple whilst others are a pale green with red veins.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
The pitchers, or which there are several (maybe about 8) per flowering stem, are modified basal leaves and are 10 to 20cm high (up to 30cm long), curved at the bottom, not quite upright, and with a curved cowl or banner at the top.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
The hoods of the pitchers usually have a striking red and yellow pattern on them, perhaps to attract insects by sight (as well as by smell). The pitcher is half-filled with water in which the attracted flies and other insects like ants, spiders and moths are induced to drown. But despite the low catchment percentage (about 1% of insects) the pitchers soon fill up with drowning and dead insects on warm days.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
Only second-year pitcher leaves can produce the necessary enzymes (such hydrolase and protease enzymes) to digest their drowned prey. Digestion of the insects is aided and abetted by the community of bacteria which live within the pitchers.


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
The flap of pitchers is just a banner for visual attraction (and maybe a very slippy landing site too?) - it does not fold over as a lid to cover the opening of the tube when an insect is caught (unlike some other species of Sarracenia plants which do).


5th July 2017, Bere Heath, Wareham Forest, Dorset. Photo: © Jill Stevens
The flowers which are about 4 to 5cm across tower above the pitchers. The petals are the 5 red-brown and at the top. Much shorter sepals (actually bracteoles) [your Author cannot make any out on these specimens] are just above where the stem joins. Hung below the 5 petals is a yellowish-green 5-lobed disc about 3cm across which is the style and is shaped like an upward curling bowl with 5 cut lobes around the edge and is hung from a single style from the ovary. The stamens, if the reader can make any out, are numerous. Between the petals is a bulging yellow-green ovary which has 5 compartments with many ovules within each compartment.

[The interloping yellow flower is the flowering spike of Bog Asphodel]

15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
Jill traversed the perils of this watery bog without the proper footwear in order to obtain photographs for the reader and your Author.
Far left at the top is an un-opened flower. The patterning, both on the outside and the inside of the open insect traps, is intriguing.


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
Some insect traps have dead insects in the bottom.


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
Two flies possibly dicing with death, lured to the traps by the odours produced especially within them. The short white stripes on the inside of the traps are appressed, downwardly-directed hairs which make it harder, once inside, to clamber out again. But not impossible, indeed, it is thought 99% of insects escape from the 'traps'. Several differing organisms contribute to the decomposition of the dead insects within: Protists (single-celled organisms which have a number of differing[!] definitions), Rotifers (microscopic organisms shaped like wheels - one such involved is called Habrotrochea rosa) and various other lodgers lurking within which remain alive to kill and half consume any insects which are mechanically trapped within the vessel by the lid which snaps shut on being disturbed by insects.


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
Two differing insects at the bottom of the trap. The trap-door has not shut on these, perhaps they have opened again when it thinks the insects are deceased or maybe they never closed(?).


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
On the extreme left is a trap which either is still developing and has not yet ever opened or was open but has now subsequently closed trapping an insect.


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
It looks like there are two black insects in this trap.


15th June 2019, Morden Bog, Wareham Forest, Dorset. Photo: © Jill Stevens
Whilst this trap has a smaller insect which may still be alive and potentially able to escape.


Not to be semantically confused with : Pitch Pine (Pinus rigida) [a tree with similar name]

Uniquely identifiable characteristics

Distinguishing Feature : The umbrella-like flower at the top and the tube-like leaves with a hood gathered around beneath them.

Pitcherplant is not native to this country, it is a neophyte which is often purposely planted in wet peat bogs. It can slowly spread.

This particular Pitcherplant (Sarracenia purpurea) smells sweet and produces a number of volatile compounds: 8.1% 2-Nonen-1-ol, 10.9% 2-Decen-1-ol, 9.7% of an unidentified ester, 11.7% α-Pinene, 6.3% 6-Methyl-5-Hepten-2-one, 4.1% Limonene, 23.5% Z-β-Ocimene, 2.1% Dimethyl Disulfide ( aka DMDS).

It is thought that some of these compounds, in particular Z-β-Ocimene and Limonene serve to attract nectar feeding insects in a variety of carnivorous plants. Likewise 2-Nonen-1-ol and 2-Decen-1-ol are known to attract a wide range of differing insect species from differing taxa, including Lepidoptera, Hymenoptera and Diptera, Coleoptera.

Dimethyl Disulfide, on the other hand, is a common indicator of protein decay and is present only after it has trapped insects and starts to digest them. The 2-Nonen-1-ol and 2-Decen-1-ol are also released during protein degradation. Blowflies (aka Bluebottles) are frequently trapped in the pitchers of Pitcherplants.

It is said that the Pitcherplant Sarracenia purpurea obtains most of its nutrients by prey capture and digestion, but this is a very inefficient process with less that 1% of the visiting insects being captured. Nevetheless, the number of dead insects being digested for sustenance within the open tube is high.


  Sarracenia purpurea  ⇐ Global Aspect ⇒ Sarraceniaceae  

Distribution
 family8Pitcherplant family8Sarraceniaceae
 BSBI maps
genus8Sarracenia
Sarracenia
(Pitcherplant)

PITCHERPLANT

Sarracenia purpurea

Pitcherplant Family [Sarraceniaceae]