YELLOW VETCHLING

Lathyrus aphaca

Pea Family [Fabaceae]

month8jun month8june month8jul month8july month8aug

status
statusZnative
flower
flower8yellow
inner
inner8green
morph
morph8zygo
petals
petalsZ5
stem
stem8round
rarity
rarityZscarce
sex
sexZbisexual

20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
Yellow Vetchling has well-separated opposite pairs of hastate-shaped pseudo-leaves and long straight flower stalks. It grows to 40cm long (up to 1m on rare occasions) and scrambles through other vegetation.


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
The flowers are on long straight stalks. There are 5 pale-green sepals; a parallel pair just above the banner, and two at maybe 180° to each other on opposite sides of the flower. The fifth in this view is hidden behind the flower.

A characteristic feature of the opposite pseudo-leaves is that they are held vertical and nearly parallel to each other.



20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
The largest of the 5 petals is the banner, which is yellow with orange-yellow stripes. It has a nick at top-dead-centre.


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
Projecting leftwards are the two shorter petals which comprise the wings, and hidden inside those are the two shorter petals making the keel.


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
Another rear view of the flower showing just the large banner with orange-yellow stripes and 4 out of 5 of its sepals. Note the stipule on the flower stalk just below the flower.


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
The main stems are not winged. The pseudo-leaves have curved veins emerging from the stalk and curving dramatically as if to to avoid the edges and seemingly terminating at or near the blunt tip.

From the angle of view of the pseudo-leaves depicted it may seem as if the 'leaf' is amplexicaul, that is, all one 'leaf' attached all the way around the stem, but it is not! From this view it is quite clearly two separate pseudo-leaves - with each one attached just 180° around the stem. The shape of each 'leaf' is triangular (or more botanically correct 'ovate-hastate' - for the sides curve slightly and the two side-ends have small slightly-triangular side-extensions).

However - appearances here are very deceptive, for what look like pseudo-leaves are actually highly modified stipules on the stem. [Stipules are small appendages in an opposite pair usually attached just underneath where the leaf-stalk attaches to the main stem of a normal leaf].



20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
The lower pair of opposite pseudo-leaves (actually modified stipules) are definitely not amplexicaul (attached to the main stem all the way around) but are split into two separate pseudo-leaves (aka stipules on Yellow Vetch). The flower stalk emerges from the main stem just above the places where the these stipules are joined to the main stem. The flower stalks are long and very straight before deflexing near the top to hold a slightly drooping yellow flower.


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
Emerging out of the side between the two large triangular leaf-like stipules is what looks like a curly 'tendril'. But with this plant being Yellow Vetchling, it isn't a tendril at all, it is actually a long wire-like leaf behaving as a tendril! So, on Yellow Vetchling, we have pseudo-tendrils which are made from highly modified leaves and pseudo-leaves made from highly modified stipules. So - where are the stiplues which might, on this tipsy-topsy-turvy plant, be made from a highly-modified other object - from maybe the real tendrils - well, the answer is that there doesn't seem to be any (or at least that is the conclusion of your Author - but he may be wrong here...).


20th June 2012, somewhere in Dorset Photo: (CC by 2.0) Geoff Toone
This is about as wide as the 'pseudo-leaves' splay from each other. Note the pseudo-tendril emerging from the junction of the pseudo-leaves and wrapping itself around a stalk of grass to help hold it stable.


Slight resemblance to : Meadow Vetchling (Lathyrus latifolius) which also has yellow flowers but the leaves and tendrils are the genuine articles, with the leaves being narrow oval with two long narrow stipules pointing downwards near where the leaf joins stem. The flowers of these are on much shorter and thinner non-straight stalks.

Uniquely identifiable characteristics

Distinguishing Feature : The relatively large hastate pseudo-leaves in opposite pairs along the stem.

Yellow Vetchling is decreasing in occurrence and is now a quite rare [RR], possibly because it is a tipsy-topsy-turvy plant where two of its main components are made from highly modified other components and it's quite difficult for it to accomplish this magic trick (your Author surmises). It seems to be the only species of Lathyrus (and there are at least 15 other species occurring in the UK) which has stipules masquerading as leaves and leaves masquerading as tendrils.

It is thought to be probably native, and occurs scattered, mainly in the South and South-East of England and the Channel Islands. It occurs sporadically a bit further north as a casual. It grows on dry embankments, on rough ground and in dry grassy places.

The seeds are toxic if eaten in sufficient quantity and can cause a serious malady called lathyrism which is particularly relevant with cattle and livestock. But because it is so rare, this constitutes a much reduced risk; there are other Lathyrus species which are far more abundant and widespread.


  Lathyrus aphaca  ⇐ Global Aspect ⇒ Fabaceae  

Distribution
 family8Pea family8Fabaceae

 BSBI maps
genus8Lathyrus
Lathyrus
(Peas)

YELLOW VETCHLING

Lathyrus aphaca

Pea Family [Fabaceae]