LESSER TREFOIL

Trifolium dubium

Pea Family [Fabaceae]

month8may month8jun month8june month8jul month8july month8aug month8sep month8sept

status
statusZnative
flower
flower8yellow
morph
morph8zygo
petals
petalsZ5
type
typeZclustered
type
typeZglobed
stem
stem8round

31st May 2009, East Lancs Rd, Moorside, Gtr M/cr. Photo: © RWD
Sprawls low amidst dry short grass barely reaching 25cm in height. Also a lawn weed.


31st May 2009, East Lancs Rd, Moorside, Gtr M/cr. Photo: © RWD
Flowers a deeper yellow than those of the similar but larger Hop Trefoil.


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
A low erect to sprawling annual growing up to 25cm, this one held aloft to enable the viewer to better espy its features. The often globular flower heads can be at the summit of stalks, or in the branch or trefoil leaf axils.


31st May 2009, East Lancs Rd, Moorside, Gtr M/cr. Photo: © RWD


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Sometimes turns purple, as here, when under stress such as too much sun or lack of some nutrient. Leaves are trefoil.


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Flower heads, at just 3-4mm across, are smaller than those of Hop Trefoil at 4-7mm across. Here some of the leaves are displaying apical points at the tip, which many books in-correctly state that they lack: the absense of a point is not a good identifying feature, but the smaller number of flowers (<20) on each flowering head is.


31st May 2009, East Lancs Rd, Moorside, Gtr M/cr. Photo: © RWD


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
The number of florets in a flower head is mostly less than 25 [(3)5 to 20] (whereas for Hop Trefoil the number of florets is usually greater than 25). (The flower at the top has yet to grow longer, the sepal teeth are still wrapped around it)


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Sepal teeth unequal in length as they are on Hop Trefoil and the larger still Large Trefoil as well (but equal in length on Slender Trefoil).


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Sepals are all fused together and hairless (hairy on the similar Black Medick with which it is often confused). Also has deeper-yellow flowers than Black Medick.


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Flowers a deep yellow.


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Sparsely hairy. Persistent corolla before the development of fruits.


27th June 2015, Knowsley Safari Park, Prescot, Merseyside. Photo: © RWD
Often lacks the minute point at the tip of the leaflets which the similar Black Medick always presents, but the lack of a point is not a good identifying feature: many Lesser Trefoil leaves do indeed have a point at the tip, as well as a few teeth near the end.


Easily mis-identified as : Black Medick (Medicago lupulina) (when not in fruit) and with several other similar species:

Compared to Lesser Trefoil, which has (3)5 to 20 yellow flowers in a cluster, which is 3-4mm across and a hairless calyx, the flowers themselves being 3-4mm long, and sepals fused together with un-equal sepal teeth :

  • Large Trefoil (Trifolium aureum) has >20 golden-yellow flowers in a cluster, which are much larger at 12-20mm across (larger than all the others), the flowers themselves being 5-8mm long (longer than all the others), and much larger but still un-equal sepal teeth which are also toothed on the edges.
  • Hop Trefoil (Trifolium campestre) has >25 pale-yellow flowers in a cluster, which are larger at 8-15 mm across, the flowers themselves being 4-7mm long, and larger but still un-equal sepal teeth.
  • Slender Trefoil (Trifolium micranthum) has 1(2)-6(10) yellow flowers in a cluster, which are 4mm across (smaller than all the others, except for Black Medick whose cluster size can overlap); the flowers themselves being 1.5-3mm long (smaller than all the others), but with sepal teeth all equal length. But un-like all the others has fruits which are 1-2 seeded (rather than just 1-seeded of all the others)
  • Black Medick (Medicago lupulina) has 'numerous' (10-50) yellow flowers in a cluster, which is 3-6mm across, the flowers themselves being 2-3mm long, the fused-together sepals being hairy, the leaves being downy with a minute 'prickle' at the tip, the big difference being in the spirally coiled fruits, which again like all but Slender Trefoil have but one seed.

Grows in bare places, rocky outcrops, and open ground dry grassland.


  Trifolium dubium  ⇐ Global Aspect ⇒ Fabaceae  

Distribution
 family8Pea family8Fabaceae

 BSBI maps
genus8Trifolium
Trifolium
(Trefoils)

LESSER TREFOIL

Trifolium dubium

Pea Family [Fabaceae]