Monday, June 15, 2015

botanist in bath

A couple of interesting plants seen during yesterday's visit to Bath. 

A weird-looking bramble, growing among "normal" brambles, on the edge of the park at Bear Flat. With the help of the internet I've pinned this down to Rubus laciniatus, a species that's been given various English names, including Parsley-leaved Bramble, Fern-leaved Bramble, Evergreen Blackberry, and Cutleaf Evergreen Blackberry. (French: Ronce laciniée. Dutch: Peterseliebraam.)

The stems have thorns; the buds have distinctive elongations; the petals are relatively narrow and 3-lobed (or double-notched, if you prefer).

The black fruit is said to have a delicious flavour, "fruitier" than most R. fructicosus agg.  I pass by this spot fairly often, so I might get the chance to check it out.

Rubus laciniatus is now a global traveller, well-established as an escape from cultivation in NW Europe, USA, Australia and New Zealand (see  the map on this useful Dutch site). Wikipedia says it's native to Europe, but no native range is known. According to Mansfeld's Encyclopaedia of Agricultural and Horticultural Crops (English edn 2001, Peter Hanelt etc): "First cultivated (since late 17th cent.) in England. Most probably originated there as a mutation of R. nemoralis P. J. Müller, but not known in the wild."  It is most commonly grown in the thornless form "Thornless evergreen".
I don't know why the parent is surmised to be R. nemoralis in particular, a bramble with round leaflets and a long terminal pedicel. [Description here (in German):]

Stace, on the other hand, separates the two taxa.  He place R. laciniatus in Rubus Sect. 2. Glandulosus Series Sylvatici and  R. nemoralis in Series Rhamnifolii. He describes R.laciniatus as an alien species, "origin unknown". Interesting subject for some DNA analysis, I'd say.

From Bear Flat, we took the Linear Park walk (Two Tunnels cycleway) down to the Lower Bristol Road, then crossed the river and came in to the city centre through Royal Victoria Park,

Here in the city centre, I found my second plant.

This is the neophyte grass Polypogon viridis (Water Bent, Water Beard-Grass). It seems to like dry-ish waste ground here, though in its native Mediterranean region it's associated with water. Whether that water is strewn with fag-butts I don't know, but I wouldn't be surprised. Anyway, the UK is always relatively wet by Mediterranean standards. An increasing species. (I was told it's now widespread in Bristol.)  

In Hubbard (3rd edn, 1984), this grass - then described as "rare" - is called Agrostis semiverticillata. Hubbard was aware of the other name and commented: "Water Bent resembles Polypogon in its pedicels being articulated and falling attached to the main spikelet and in its epidermal structure, but this genus may be readily distinguished by the 2-notched or 2-lobed and awned tips of the glumes". Apparently this argument didn't carry the day, and the plant is now accepted as Polypogon despite its unlobed and unawned glumes.

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