Sunday, 27 April 2014

Barholm and Greatford

Euphorbia helioscopia

Having suffered with a niggling back injury, I decided not to go too far yesterday, so drove out to Barholm, north-east of Stamford, and did a circular walk via Greatford. The first part of the walk was along a public footpath, first through an area of improved grassland and then a rape field. The latter had quite a few arable weeds coming into flower, including dove's-foot crane's-bill Geranium molle, field pansy Viola arvensis and sun spurge Euphorbia helioscopia.

The most interesting of the arable species was common fumitory Fumaria officinalis. I love the finely-dissected blue-grey smoky foliage that gives it its generic name, and the two-tone purplish flowers are exquisite.

Fumaria officinalis subsp. wirtgenii

Fumitories are tricky to identify and I always take a sample back to check. There are two distinct subspecies of Fumaria officinalis, and this one proved to be F.officinalis subsp. wirtgenii, which is the more frequent on light soils in eastern England, and worth looking out for in arable fields on the limestone or sandy soils. The racemes are normally 10-20 flowered, and the spathulate lower petal is truncate at the apex, rather than pointed. The fruits of this one were rather young, but they are about as long as wide (whereas subsp. officinalis has fruits which are wider than long) and often have a distinct apiculus. 

Truncate shape of lower petals of F. officinalis subsp. wirtgenii

Fruit shape, with apiculus

In Greatford there was a rather nice roadside ditch with a good range of aquatic species, while back in Barholm, stone walls proved to be quite rich, although also posed a dilemma. One wall, running between a farm and a garden had a number of species of Sedum as well as the house-leek Sempervivum arachnoideum. Had these established naturally (they were surrounded by moss and other native species such as Erophila verna) or had they been placed there deliberately?

Sempervivum arachnoideum

Sedum spathulifolium

Towards the end of the walk I came across a hedgerow weeping willow. Willows are notoriously difficult to identify, and early in the year the leaf characters are often unreliable. There are two taxa of weeping willow which you're likely to come across - Salix x sepulcralis and S. x pendulina. Fortunately this tree still had its female fruits, and the elongate, conical shape which are much longer than the subtending bracts make this one S. x pendulina.

Elongate fruits of S. x pendulina

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