Heracleum branca-ursina

As we head into peak hogweed season I'm reminded that I never got round to posting these photos from last year. Bear's Breech Hogweed (Heracleum branca-ursina) is one of those Sell and Murrell taxa that is not fully resolved and merits further investigation. Seen as a colony it is striking and distinctive, typically well over 1.5m tall rather than the more usually waist high Hogweed (Heracleum sphondylium). The outer flowers (and seeds later) are also very large.

This all said, the two species do seem to overlap and I would be very cautious about recording the former based on flower size alone. Its not unusual to find perfectly normal Hogweed with flowers larger than stated in the Sell & Murrell key. In my view and based on relatively few encounters it is probably more defensible as a variety of Hogweed, rather than a distinct species or subspecies. I don't think there are any significant barriers to inter-breeding. One of my first encounters with this plant was at Sun Lane Nature Reserve (VC64) where there was a nice stand, and then plants with and grading towards Hogweed with increasing distance from the main stand.

The other big question is where it comes from. It seems to be an introduction, and a relatively short-lived one at that in the few locations where I have known it in the past.

Below is a selection of photographs taken last June in a sunny glade in plantation woodland at Temple Newsam (VC64).

Heracleum sphondylium inflorescence (left) and branca-ursina (right)

Heracleum branca-ursina with 2 pence coin for scale

Colony of plants 2m or more tall (I'm 5' 7'' and these towered above me)

Typical foliage which has quite a distinctive jizz, in terms of shape, size and texture. Hard to put into words and best understood firsthand

Variegated Yellow Archangel (not that one!)

I was privileged this week, after 7 weeks of lockdown, to be legitimately allowed out to undertake an ecological survey near Mirfield (VC63). A blissful day in an ancient woodland, and likely to be my one such experience this spring.

A pleasant surprise during the day was the discovery of a colony of the white-speckled native form of Yellow Archangel (Lamiastrum galeobdolon subsp. montanum var. variegatum). I only see this form rarely and then only in the best woodland habitats. The last time I found it, it was in a location where a previous recorder had identified the plant as the non-native subsp. argentatum, a controlled weed species. The possible consequences of reporting a native plant as a controlled weed are obviously best avoided.

It is a much more delicate species than the undesirable form. The leaves are generally smaller and less marked, with none of the chocolate-brown coloration over autumn to spring. It is also much less inclined to form a spreading carpet because it tends to die-back during the winter leaving only the growing tips. The general impression is of discrete plants rather than a cohesive mat of stems.

Buttercups and Hawthorn

After a long break, I'm well overdue picking up this blog again. 'Lockdown' has provided an opportunity over recent weeks to explore familiar sites and routes in closer detail, and I have been pleased to find plants not noticed before. Some plants have probably only been missed in previous years because the last time I walked that way they were obscured by other vegetation. The positive of lockdown botanising is that you walk the same routes over and over again as the season changes.

I have collected more photos along the way than I've yet found the energy to turn into blogs. So to get me started again, I am going to try and post regular snippets rather than try to be more ambitious.

First up are two attractive forms of native plants found yesterday. One is a truly wild, while the other will be of planted origin.

The former is this stunning form of Bulbous Buttercup (Ranunculus bulbosus) found in a pasture near Scholey Hill (VC63). Three plants mixed with others of typical flower colour. This seems comparable with (but isn't) the cultivar known as 'F.M. Burton.'

Next up at Oulton (VC63) was this hawthorn (Crataegus x media 'Punicea') in a hedgerow between two arable fields. It is supposedly a form of this native hybrid (its nothing like Midland Hawthorn C. laevigata, despite some references stating this) but if so its seems to be much closer to Common Hawthorn (C. monogyna). I did find one photo online that suggests that it might occasionally produce two styles rather than the usual one, but as per Stace this is not 100% reliable for the hybrid. I also note that Sell & Murrell list it under Common Hawthorn, so it seems the species affinities are yet to be adequately resolved.

Eastern Parsnip Reaches Leeds

Eastern Parsnip (Pastinaca sativa subsp. urens) is a recent edition to the British list and appears to be spreading rapidly. The only positive of my taxi ride home today due to the inadequacies of the British rail network is that it allowed me to spot it in a number of locations on the road network. Definitely one to watch out for elsewhere in the region, it seems to favour road margins and the central reservation. See Stace 4 for the distinguishing features (once known it can be told at a glance), and check out its current distribution here. Currently Leeds is its most northerly outpost.

Photo by Emmanuel Stratmains (www.tela-botanica.org via Wikimedia Commons)

Photo by Mathieu Menand (www.tela-botanica.org via Wikimedia Commons)

Cicerbita at Clapham

Friday was the last day of the BSBI Summer Meeting and the rain finally returned. On route home I thought I would stop in Clapham to check out a Pirri-pirri-bur (Acaena) record that need a second look. Perhaps more on that later.

I had not visited Clapham in summer before, so I thought it a good opportunity to poke around the village for other plants of interest. Of course the Common Blue-sowthistle was in full bloom, so an easy tick for Cicerbita macrophylla subsp. uralensis. After all, all the Floras will tell you that this is our plant.

Cicerbia macrophylla subsp. uralensis

A little further on I found a new stand, but it didn't sit right. Huge plants towering over my head, stupidly large terminal lobes on the basal leaves and altogether too robust. It was also very glandular in the inflorescence which I did not remember noticing before in this species. So back again I went to the first stand for a second look, and yes half the height, more flimsy, smaller foliage and scarcely hairy in the inflorescence. Quite a different jizz. So what was it?

I was expecting one of the other naturalised species, but the leaves were wrong. So next stop with an alien is to visit the excellent Alien Plants of Belgium website, and lucky for me I was straight to an answer. Cicerbita macrophylla subsp. macrophylla. Key below.

• Terminal lobe of basal leaves up to 40 cm long. Lowermost inflorescence branches 2-3,5 mm wide at base. Glandular hairs in inflorescence very dense, unequal in length (0,5-2 mm long). Stem up to 300(-350) cm tall === subsp. macrophylla

• Terminal lobe of basal leaves up to 25 cm long (often less). Lowermost inflorescence branches 1-2(-2,5) mm wide at base. Glandular hairs in inflorescence often less dense, subequal in length (ca. 1 mm long). Stem up to 200 cm tall === subsp. uralensis

This seems to be the first record for Britain. Is it likely to prove more widespread? Perhaps. It is probably no coincidence that it is naturalised in Clapham, given it was the home of legendary plant hunter and collector Reginald Farrer. Still, one to look out for elsewhere regardless of received wisdom.

Cicerbita macrophylla subsp. macrophylla

New for Yorkshire

Just back from an enjoyable week at Malham for the BSBI Summer Meeting. More on this to follow soon, but also see the daily accounts on the main BSBI blog.

The first good find of the week didn't take very long. With a little time to kill on the first day, while I waited for everyone else to arrive, I had a stroll round the grounds of Malham Tarn House. Examining the rock cutting by the driveway I found what looked a very odd Caucasian-stonecrop (Sedum spurium - conscious use of the old name here as the database is yet to catch up with Stace 4). The plant looked far too delicate, and the leaves a little too petiolate. So into the pocket it went to look at later.

It didn't take too much effort later to get it to Lesser Caucasian-stonecrop (Sedum stolonifera). The obscurely* papillose leaf margins providing the final confirmation. A first for VC64 and Yorkshire. Surely a species to actively search for elsewhere, as it is probably overlooked.

*correction from original post, stolonifera is obscurely papillose i.e. small raised bumps. In comparison spurium is obviously papillose with long papillae (longer than wide). You can feel them with your finger towards the tip of the leaf.

Ivy Broomrape - Another Huntingdonshire Site

Barry Dickerson has just found a new location for Ivy Broomrape (Orobanche hederae) on Cambridge Street, St Neots. Based on the photo provided it seems well established. This is only the second record for the county, and it must surely be a deliberate introduction. This a species that is well known around Cambridge in VC29, but the nearest and only other VC31 record is from Godmanchester.