RIVER TRENT, GIRTON TO HOLME. + DCW
The search for Oak-leaved Goosefoot continues. This time at low tide, based on the river below Cromwell Lock being 4-5 hours after the predictions for Hull. We started at Girton where the sailing lake, devoid of birds had two sizes of pond-skater and these are three of the bigger ones.
The one I get on my pond and that I’ve seen elsewhere, I have always taken to be Gerris lacustris but it seems that G. odontogaster is a likely companion and G. argentatus is possible too. These though are 7 to 10mm long so the one in the photo must be the ‘widespread and abundant’ Gerris najas at 13-17mm.
On the walk northwards to the C. glaucum site we found a freshly deceased juvenile Blackbird with no external injuries and the conclusion of our post-mortem was an unexplained death.
This is the gall of the gall fly Urophora cardui on Creeping Thistle. The adult fly which emerges in June-July lays eggs between the immature leaves. The second-instar larva then burrows into the stem, inducing the plant to form gall tissue which is soft on the inside and woody on the outside with one to several chambers where the larvae then hide safely away, munching on the soft gall tissue. Safe that is until Eurytoma serratulae comes along. This is an ectoparasitoid chalcid wasp which induces U. cardui to form a puparium – in which it overwinters. But it doesn’t end there. Eurytoma robusta may come along and parasitise E. serratulae. As an endoparasitoid, it lays its eggs on the third-instar larva (of serratulae) or just randomly in the gall tissue with the larva consuming both the fly and the wasp – unless that is the puparium has formed in which case E. robusta doesn’t survive.
If neither of the chalcids get the fly, it has to hope that its mother chose to lay its eggs on a thistle that is growing in just the right place for the plant to wither into wet ground so that the gall is sufficiently dampened for that woody external tissue of the gall to become soft enough for the adult to tunnel its way out.
Mudwort Limosella aquatica is, as far as I know, much simpler. It likes shallow puddles. It is very scattered and decreasing and has tiny flowers but you have to lie down next to them with a lens to see them so I didn’t bother.
Brassica rapa subspecies campestris can also be called Wild Turnip but it grows along the navigable stretches of the Trent and Bargeman’s Cabbage will be my preference.
Technically this should be Hylotelephium sp. as it has been re-christened by the latest Stace (formerly section Telephium).
It can’t be identified specifically without the open flowers, but the app, PlantNet thinks it is Orpine, Hylotelephium (Sedum) telephium which is the native plant though it is not native in this Trentside hedge-bottom. It had alternate leaves so if it’s not that it must be H. ‘Herbstfreude’, the hybrid between telephium and spectabile.
These are still Sedums and the two commonest on dry, bare ground. Up close, White Stonecrop (on the left) and Biting Stonecrop are very different but from 5’9″ away, I find the difference not so obvious. Dave has zoom vision or a lot more practice.
Smooth Catsear Hypochaeris glabra is another one that Dave shows me when we visit the sand lands north of Newark. It doesn’t much look like common Catsear to me but if needs be, the ray florets of the rare one are hardly longer than the longest bracts (which are purple-tipped). It only likes sunny mornings so goes to bed at other times.
It became quite hot later in the day as we scoured the banks of the river in our quest for the elusive goosefoot near Holme. As well as Common Sallow moth, we found more Silver Y and a Blood-vein and butterflies included Small Copper with a couple of Common Terns, 8 Curlew, about 10 Little Egret, 1 Hobby and a Common Sandpiper.
I got very mixed up on this one which I take to be Alisma plantago-aquatica but Dave seemed to be saying it was something else that I’d never heard of. I’ve now looked in the books for related species so now I must have heard of it but I still can’t see what it is!
I have been enlightened….This is actually Alisma lanceolatum Narrow-leaved Water-plantain and I must put it down to tiredness, laziness and confusion that I couldn’t see that for myself. I think reference to Rose et. al. may have been partly to blame but a re-read clarifies it. It is not that uncommon, but was quite unfamiliar to me. When I started out on birdwatching, I had already spent years of my childhood browsing bird books so anticipated many of those obscure and exotic species. Being aware of plants that are similar to the everyday ones is an important aid in picking out the scarcities.
The garden of the Muskham Ferry looked inviting but it would be a long swim as there is no sign of the ferry itself.
The telegraph pole means that I get nil points for composition in this picture and taking a chain saw to it would probably be easier for me than ridding it by photoshop. Maybe I should have used the picture of the very big Walnut tree near where I was stood?
What? This one?
