National Botanic Gardens Autumn '13

I've been based at The NBGW for the last month as my MPhil deadline is fast approaching and it helps to be far from the myriad lights of Aberystywth. Most of my time has been spent in front of a computer or with a pipette in hand desperately making up for lost time. However I have been out into the world as the old farm house that serves as accommodation for myself and a few other students is a short walk across the gardens and through some damp cattle fields. On these twice-daily trips I've noticed a few plants beyond those planted by horticulture.

The first of these grows in the slate beds where the path enters the gardens. Veronica peregrina is a small speedwell introduced from North America. Its tiny whitish flowers subtended by long bracts don't leap out but once I'd noticed it I found it to be abundant in a small area but absent elsewhere, perhaps suggesting it to be a recent arrival. The picture below shows a particularly large individual the majority being so small as to remind one of Montia fontana at first glance. It is scattered about the UK with a few centres of abundance (or recoding awareness) including Liverpool and Northern Ireland and is mostly associated with gardens. Only one previous record exists from Carmarthenshire.       

Veronica peregrina,
Slate Beds, NBGW, Sept 2013

Between the gardens and the fields is a long artificial lake with Little Grebes and Teal feeding among a sea of duckweed. One morning I finally got round to fishing out a handful and found three species to be present. Spirodela polyrhiza made up the vast majority but a few fronds of Lemna minor and Lemna trisulca were also present. Lemna minor is, of course, abundant throughout the British Isles but the other two are relatively uncommon in the west of Wales. 

Spirodela polyrhiza, Habit,
Lake, NBGW, Sept 2013

I've been trying to pay more attention to duckweeds as there are a number of species of interest and they often don't get much of a look in. One introduced species, Lemna turionifera, was added to the British list in 2007 in this paper by Richard Lansdown and has since been found in a few places scattered across the south of Britain. Another species, Landoltia punctata, is also mentioned by Lansdown as having been found in aquatic nurseries in the UK but is not yet known from the wild. This very impressive duckweed website has a lot of information on these species and others as well as useful pictures, keys and introductory duckweed material.  

Spirodela polyrhiza, Underside of frond, Lake, NBGW, Sept 2013

Fringing the lake are tall herbs and bulrush. Almost certainly planted but rather pretty none the less is Typha angustifolia. The smaller and thinner of the two British bulrushes this species is uncommon and mostly introduced in the west. It hybridises with the commoner T. latifolia though I could find no evidence of this having happened at the Gardens despite both species growing adjacent.

Typha angustifolia, Lake, NBGW, Sept 2013