I am currently at Aberystwyth University studying for an KESS MPhil in the population dynamics of glasshouse weeds. I'm a couple of months in and I've just progressed from many weeks spent wading through the literature and onto my first visits to actual glasshouses. In an effort to develop a survey protocol I have visited many of the glasshouses in and around Aberystwyth over the last few days. I also made my first visit (in many years) to my KESS partner organisation, The National Botanic Garden of Wales.
My literature review on the subject of glasshouse weed assemblages turned up surprisingly little information. I found only a single paper describing the floral assemblages in any detail. This solitary paper details the glasshouse weeds of a Polish Botanical garden. Considering the huge diversity of structure and function within the protected environment (greenhouses, polytunnels, etc.) as well as its economic importance I find it puzzling that no further research exists in this subject area. This lack of previous information makes a wide-ranging survey the only logical first step in my research.
So the results of my initial, very limited and provisional, survey of thirty-four Aberystwyth glasshouses turned up around eighty species.The season limited both what was visible and what could be identified so the actual number of species in the surveyed glasshouses is certainly greater than my current enumeration. The most frequent species (listed below) were unsurprising. Some of the frequent but not universal species were less expected. For example Geranium lucidum, a species that occurred frequently both in the Aberystwyth and NBGW glasshouses but one I would not immediately have associated with the habitat.
Species occurring in 10 or more of the 34 Aberystwyth glasshouses surveyed (listed in order of frequency of occurrence).
- Epilobium sp.
- Oxalis corniculata
- Cardamine hirsuta
- Poa annua
- Euphorbia peplus
- Stelaria media
- Senecio vulgaris
- Taraxacum officinale agg.
Some of the more interesting weeds were those that had simply spread from one side of the glasshouse to the other. A particular feature of the varied glasshouses in the University Botanic Gardens at Penglais was the frequency of regenerating pteridophytes. Three species that seemed particularly successful were Phlebodium aureum, Cyrtomium falcatum and Pteris cretica. These species were not only common in the heated glasshouse where they had originally been planted but had also spread to adjacent unheated glasshouses with some success.
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| Phlebodium aureum Penglais Botanic Gardens, Aberystwyth University, Cardiganshire (SN 59619 82076) 28/11/12 |
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| Pteris cretica Penglais Botanic Gardens, Aberystwyth University, Cardiganshire (SN 59619 82076) 28/11/12 |
Further interest was provided by the infallible glamour of carnivorous plants. In the most tucked away glasshouse of the already rather tucked away University Botanic Gardens there is a rather impressive collection of pitcher-plants, sundews, venus fly-traps and bladderworts. Not being an expert on any plant not native to the British Isles I relied on the labels for any indication as to the identity of the plants. In truth it mattered little as the appeal of these plants is universal and even for a cataloguer such as myself it was easy to appreciate their exquisite adaptations without needing to know their identities.
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| Sarracenia leucophylla Penglais Botanic Gardens, Aberystwyth University, Cardiganshire (SN 59676 82089) 28/11/12 |
A somewhat odd highlight of my visit to the NBGW was seeing two of Snowdonia's most enigmatic alpine plants. Admitted both were in pots, a fact that somewhat detracted from the excitement.
The first of these is a plant that I am now quite familiar with in its Irish settings but one that has a quite mysterious history in Wales. Saxifraga roseacea subspecies roseacea, the Irish Saxifrage was, according to the Welsh Red Data List, last seen in Snowdonia in 1970 (1). I am not sure of the details of the 1970 record but the material in cultivation at the gardens and elsewhere stems from a collection made by the legendary North Wales botanist Dick Roberts. The information I can find suggests that the collection was made in 1962 and was of a single unattached sprig from Cwm Idwal (2). The staff and students at the NBGW are currently conducting genetic studies on Welsh and Irish material to determine the if there is any difference between the accessions. I have carefully checked any Saxifraga hypnoides type plants I have encountered in the mountains of North Wales but have, as yet, not managed to rediscover this most enigmatic of Welsh alpines. Below are two pictures of Irish S. roseacea subsp. roseacea each looking very different and each growing in very different situations. The first in steep Philonotis flushes in a shaded corrie on the east flank of Mount Brandon in Co. Kerry and the second on exposed dry limestone pavement on Inisheer, the smallest of the Aran Islands. This page from the BSBI plant crib contains helpful leaf outlines of this group of species. Also, from the Herbaria@home page, here is a nice specimen from 1918 apparently collected somewhere on Snowdon.
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| Saxifraga roseacea subsp. roseacea Mount Brandon, Co. Kerry (Q 46282 12593) 25/08/12 |
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| Saxifraga roseacea subsp. roseacea Inisheer, Co. Glaway (L 99027 01612) 01/08/11 |
The second plant is probably one of the rarest species in the world if species is the correct term for this apomitic taxon. Hieracium snowdoniense, as detailed in this paper, is a Welsh endemic of which only one individual is currently known in the wild. It was previously recorded slightly more widely across the three main massifs of Snowdonia but was long thought extinct until the rediscovery in 2002. Seed was collected by Tim Rich in 2002 from the single wild plant and it is from this collection that the plant below derives. Had I come across this plant in the wild I would not have been able to put a name to it with any certainty but the specimen below is helpfully labelled and barcoded.
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| Hieracium snowdoniense NBGW from material collected in Cwm Idwal, Caernarfonshire |
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