Editor :

R Middleton
12 Meaux Road
Wawne
East Riding of Yorkshire
HU7 5XD

email:
r.middleton@hull.ac.uk

Of Walnuts and Harlequins

While examining the municipal plantings along Holwell Road, Hull [TA 10 32] in September 2007, I was surprised to find a large group of Walnut trees planted as a small copse alongside the dual carriageway. Although known as single trees in Hull and the East Riding, the Walnut (Juglans regia) is by no means common and to find a group is noteworthy. A closer examination of the planting revealed that, along with the 40 or so Walnut trees were some Sea Buckthorns (Hippophae rhamnoides) and four American Black Walnuts (Juglans nigra).

The Walnut is not included for v.c.61 (South-east Yorkshire) in the Botanical Society's vice-county census catalogue (Stace et. al. 2003), neither does it feature in Crackles's 1990 Flora of East Yorkshire from which it has been excluded, presumably on the grounds that it only ever occurs as a deliberate introduction. It was thus very pleasing to find that several seedlings were growing in the vicinity, some in positions which excluded the possibility of deliberate planting. The specimen shown on the right was rooted up against a factory wall, across the footpath from the main plantation. Whether the sapling had grown from a fortunately placed fallen nut or one deliberately hidden by the Grey Squirrels now found in the area cannot be determined but, whatever the cause, it provides a new vice-county record.

It is somewhat embarassing that a grove of large trees can go undetected in such a conspicuous and accessible area. I must have passed the trees dozens of times since they were planted and never noted their existance. In this case it was the presence of the fallen fruits on the footpath that drew my attention to their presence. In excuse I must say that the pinnate foliage does bear a passing resemblance to Ash (Fraxinus excelsior), a similarity even more marked with the Black Walnut trees.

Although the Common Walnut has now established its place in the vice-county flora, the American Black Walnut still has a way to go. The Black Walnut bears much more than a passing resemblance to the Ash, the leaves being so similar that they would hardly elicit a second glance. Even the trunk of the tree bears a closer resemblance to that of a mature Ash than to the smooth bole of a Common Walnut. The photographs on the right show the clear distinction between the two Walnut species.

The fruits are, however distinctive. The Common Walnut fruit looks very much like a smooth Horse-chestnut, with an ovoid and strongly aromatic case which splits readily to reveal the familiar (and delicious) nut. The fruit of the Black Walnut is much more globose with a rougher surface. Although I have yet to find reference to this in any of the books, the strong aroma is much more remeniscent of cheap toilet soap and, to me anyway, slightly unpleasant. The roughly textured nut is notoriously difficult to extract from the husk and then equally awkward to crack and extract the small kernel.>

As if the discovery was not enough for a single day, I was intreagued to note that the slightly sticky Walnut trees supported a population of large orange Ladybirds with larvae, pupae and adult insects all present. the photograph on the right shows a large and very active larva.

The adult insects (shown on the left) were rather large for the more common British Ladybirds and later examination of a "captured" specimen showed it to be the alien Harlequin Ladybird (Harmonia axyridis succinea). Althought first recorded in Britain as recently as 2004, it has now spread up from the south east of the country, through the Midlands and over the Humber. It seems likely that the rapid spread will continue relatively unchecked. The spread is currently monitored by the UK Ladybird Survey and much useful information is available from their website.

The adult insect is very variable in colouration and patterning but all of the individuals seen at this site were of the same "succinea" form - i.e. orange with 19 or 20 dark spots.

Examination of the roadside planting in the area revealed the following species:

Juglans nigra, Juglans regia, Fagus sylvatica, Quercus sp., Betula pendula, Alnus glutinosa, Carpinus betulus, Corylus avellana, Tilia sp(p)., Populus spp., Populus alba, Salix spp., Rubus fruticosus agg., Rosa spp., Prunus spp., Cotoneaster sp., Crataegus monogyna, Ulex europaeus, Hippophae rhamnoides, Cornus sanguinea, Frangula alnus, Fraxinus excelsior. Viburnum opulus

Of these shrubs and trees the only ones colonised by the Harlequin Ladybirds seemed to be The Common Walnut (Juglans regia) and the Dogwood (Cornus sanguinea). A rapid examination on 23 September 2007 showed adult/pupa/larva counts of 3/52/14 on the Walnut and 4/41/3 on the Dogwood. Single pupae were found on a Hazel and a Bramble.

During late September and October further sites for the Harlequin Ladybird have been discovered in the region. A very large colony has been found on Sycamore (Acer pseudoplatanus) near the KC Stadium, Hull [TA 07943 28868]. At this site many hundreds of insects are present with representatives of both the black with four spots (spectabilis) and the black with 2 spots (conspicua) forms. Andrew Ashworth has discovered a colony in Cottingham and Ann Rayner another at the University Campus on Cottingham Road.

Bibliography

Crackles, F. E. 1990. Flora of the East Riding of Yorkshire. Hull University Press, Hull.

Stace, C. A., Ellis, R. G., Kent, D. H. and McCosh, D. J.(eds.) 2003. Vice-county census catalogue of vascular plants of Great Britain, The Isle of Man and the Channel Islands. Botanical Society of the British Isles, London.

Field visit to Cowden

November 2007

The Society's organised trip to the disused Cowden bombing range provided a rare opportunity to visit this unique site. Since being taken over by the military in the 1930s this large cliff-top area, north of Albrough, has experienced little agricultural improvement and is now a region of scrubland, crossed by ditches and overgrown hedges, with occasional ponds. The dominant character is wet and heathy.

The Litle Auk, photographed on the right, was encountered on one of the larger ponds. It was a straggler from a large passage of birds returning north to the Atlantic after being blown into the North Sea by recent gales.

Field visit to Tophill Low

January 2008

Ten members and friends attended this meeting on an overcast but unseasonably warm Sunday in late January. Good numbers of waterfowl were present on the large "D" reservoir but without the diversity sometimes seen at this time of the year. Wigeon predominated but there were also good numbers of Goldeneye and Ruddy Duck. The highlight here was the excellent, if distant, views of a Common Buzzard hunting along the banks of the River Hull.

The bird feeder in the visitor centre afforded good views of Tree Sparrows with fleeting glimpses of Brambling in the hedge behind. The hide overlooking the borrow pit at Watton Nature Reserve, pictured above, proved very productive with Curlew, Greylag Geese, Shoveler, Teal, Gadwall, Pochard and Mallard amongst the birds seen. A drake Smew, which had been seen earler in flight, proved rather elusive up until the time the Society's chairman departed. After this it emerged from the reeds and defiantly provided excellent viewing.