Proto-Carnivorous Plants

CUT-LEAVED TEASEL

Dipsacus laciniatus

Teasel Family [Dipsacaceae]

month8jul month8july month8aug month8sep month8sept

status
statusZneophyte
 
flower
flower8white
or
flower
flower8pink
pale-pink
morph
morph8hemizygo
 
petals
petalsZ4
 
type
typeZglobed
 
stem
stem8angular
 
stem
stem8ribbed
 
stem
stem8hollow
 
stem
stem8spines stem8thorns
prickles
contact
contactZlowish
 
sex
sexZbisexual
 

18th July 2014, Liss, Hants. Photo: © Dawn Nelson
Unlike Wild teasel, which grows up to 2m high (maximum 3m) Cut-leaved Teasel can grow up to 3m high (max 4m). This specimen does look more like 3 and a bit metres high (compare with the telegraph pole which are mainly of standard height (8 to 10 metres one website claims, another says 7m - so, take your pick or get your theodolite out and calculate from triangulation).


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
Each pair of leaves may have a pair of branched stalks bearing either more leaves and/or the inflorescence(s) at the top. Unlike the leaves of Wild Teasel these leaves are raggedly cut to maybe just beyond midway to the white central rib.
The leaves are in opposite pairs well spaced out up the stem (which is hollow), the upper ones cupped to the stem and capable of holding rain water just like Wild Teasel leaves. The lower pairs of leaves are separate and just cannot hold water...


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The stems are stout and ribbed, with few but short and softer less painful prickles.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
Just beneath each flowerhead are long leafy bracts of various lengths.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The flowerheads themselves are egg-shaped and packed with numerous long, narrow, almost straight spikes. The spikes are either white or pale-pink (here white). Between them should be small 4-petalled flowers but your Author can see none.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The spikes on the inflorescence are white, as here, or sometimes pale-pink. [A different species of flower are nearer the brick wall]


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
Some leaves collect water around the main stem as on this opposing leaf-pair.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The leaves are lobed to maybe halfway to their centreline hence the common name Cut-leaved Teasel and the specific epithet 'laciniatus' in the scientific name. Even the lobes can be lobed with tinier lobes.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The lobes can vary in shape. Each leaf has a white tapering midrib like those of Wild Teasel and several plants from the Asteraceae family such as Prickly Lettuce, Melancholy Thistle, Prickly Sow-Thistle and many other plants.
The book says that the basal bracts are linear-lanceolate but your Author cannot make out any here.


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The smaller lobes on the lobes are rounded (crenate) and have tiny short hairs at the end. Some hairs seem to be curved aka hooked at their tips (centre, left).


18th July 2014, Liss, Hants. Photo: © Dawn Nelson
The stems are green with reddish-brown ribs. Most leaf veins radiate outwards from the white rib with less prominent veins linking between them.


Hybridizes with : Wild Teasel (Dipsacus fullonium) to produce Dipsacus × pseudosilvester - which has occurred with both parents present in Oxfordshire, Warwickshire, Cambridgeshire and Middlesex.

Resembles : Wild Teasel (Dipsacus fullonium) but that does not have leaves which are cut to halfway or slightly more.

Uniquely identifiable characteristics

Distinguishing Feature : A Teasel with cut leaves.

Apparently it is monocarpic, living for several years but flowering only for one year before dying, which may explain why there are no flowers visible in photos of the flower heads, only the vacant spaces between the long sharp bracts in the above photos from Liss in Hants. When it does flower, the flowers start in a circle around the centre of the inflorescence, which then progresses north and south. Each individual floret only flowers for one day before dying, but there are potentially up to 1500 flowers in a flowerhead (but not simultaneously). The fruits are achenes just under 1 cm long.

The upper paired leaves are cupped and collect water into which insects may fall and drown. Although Teasel is only proto-carnivorous, not depending upon absorbing the nutrients from dead insects, but it may take advantage of those extra nutrients when available. It is not fully carnivorous, lacking the enzymes necessary to dissolve the insects, but relies more on natural decomposition.


  Dipsacus laciniatus  ⇐ Global Aspect ⇒ Dipsacaceae  

Distribution
 family8Teasel family8Dipsacaceae
 BSBI maps
genus8Dipsacus
Dipsacus
(Teasels)

CUT-LEAVED TEASEL

Dipsacus laciniatus

Teasel Family [Dipsacaceae]