Members Reports and Photos
SATURDAY 2nd and SUNDAY 3rd AUGUST 2014 PRAEGER CENTRE, NBGs
Willowherbs and Docks
The DNFC invited Geoffrey Kitchener to conduct these two Praeger Sessions. Geoffrey is the Botanical Society of Britain and Ireland (BSBI) referee for Epilobium and Rumex. He has contributed significantly to the account of Epilobium in the standard work Flora of Great Britain and Ireland by Peter Sell and Gina Murrell.
Members had been advised that in order to obtain maximum benefit from these sessions that they should familiarise themselves with the basic species of Epilobium and Rumex. In July the species will be in full flower and fruit and as the season advances the hybrids become more evident. In Epilobium, look out for excessively branched specimens, often with highly contrasting pink and deep pink colouration on the petals. In Rumex, watch for material that appears to be shedding its fruits prematurely.
The identification of Willowherbs and their hybrids.
The identification of Docks and their hybrids. A substantial portion of the afternoon was spent in the examination of material provided by members.
Leader: Geoffrey Kitchener
Bring: Members provided material of the appropriate genus for identifiction.
The text below consist of contemporaneous notes taken at the workshop and should be considered as such only and have not been checked for accuracy or completeness. Publications such as the Dock Handbook (BSBI), Stace’s Flora , Sell and Murrell and Clement should be consulted for confirmation of details and descriptions.
One of the challenges of willowherb identification is the plasticity of hybrids which may show the characteristics of putative parent to a greater or lesser extent and where one parent may be more dominant than the other. If we look at, for example, Stace’s flora we find two types of keys – the conventional dichotomous and the multi-access.
Rosebay Willowherb is not an Epilobium and hence does not hybridise
with this genus.
E. hirsutum is readily identified by its large flower size and cross-shaped stigma. It has two types of hairs – spreading and glandular; leaves have 'pot-hook' teeth and are stem-clasping.
Parviflorum also has
cross-shaped stigma; it has long hairs which are much shorter than hirsutum;
leaves just clasp stem and teeth are not as pronouncedly pothook-shaped.
Montanum also has four-lobed stigma; leaves have crisped hairs. It may have some hairs towards the top.
Palustre is found in wet places; has very narrow leaves with few teeth; margins are inrolled; filiform stolons; seeds 1.3 mm, hairs
Ciliatum : many glandular hairs on stem and looks rather similar to roseum, but petioles are extremely short and seeds are ridged (x10 lens).
Roseum has stalked leaves, often white flowers and leaf veins are prominent underneath.
Obscurum: hypanthium with glandular hairs; growth habit tends to be spreading with season.
Tetragonum: upright plant with long strap-shaped; leaves and long seed pods >= 7 cm (cf obscurum); no glands. Subspecies are known.
In general, select specimens with reasonably mature pods in order to assess length and fertility; press with open flowers where possible.
Hybrids are partially sterile.
Some hybrids encountered were ciliatum x parviflorum: leaves felty on upper surface [parviflorum]; glandular hairs; partially blind pods.
[obscurum x hirsutum v. rare.]
ciliatum x hirsutum = lots of short glandular hairs
montanum x ciliatum
parviflorum x montanum
parviflorum x palustre (Co Down specimen produced)
obscurum x palustre ???
Species tetragonum, obscurum, hirsutum, ciliatum, parviflorum, montanum and roseum all seen.
Only subgenus Rumex considered (R. acetosa and R. acetosella do not hybridise with the subgenus).
crispus x obtusifolium is a very common hybrid. The former parent has entire tepals whereas the latter is toothed. Tubercles give buoyancy and help in dispersion of seed for species that grown in or near watery places. Obtusifolius has broad leaves with cordate base; has papillae on main veins of leaf and toothed sepals. Crispus has triangular tepals, no teeth and long leaves with crisp edges. Subspecies littoreus found on seashore and nearby has 3 large tubercules. Crispus x obtusifolius is the most fertile hybrid and is very common. Look out for dock with redder stems – visible at 30-40 metres in a population.
Some of the “hydrolapathum” material presented had some characteristics of hybrid material but further work is required to find out the variation within Irish material (on lakeshores and rivers of the midlands etc).
The linguate tepal group includes sanguineus; has one tubercle only being a “woodland” species. Conglomeratus, a plant of wetter places, tends to be leafy with three developed tubercles for aquatic dispersal.
Pressing: take remains of basal leaf, lowest green leaf and upper part of plant with inflorescence ….
Keys and descriptions
Clive Stace New flora of the British Isles
John Poland and Eric Clement The vegetative key to the British flora
Peter Sell and Gina Murrell Flora of Great Britain and Ireland
JE Lousley and DH Kent Docks and Knotweeds of the British Isles (BSBI handbook) Paperback – to be reprinted shortly.
Photographs © G Sharkey
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