Seven Good Plants edition 3 – May and beyond WOODLAND Platanthera chlorantha Greater Butterfly-orchid
A native of woodland although it can also be found in scrub and occasionally on unimproved chalk and limestone grasslands. Over much of southern Britain it is regarded as an indicator of ancient woodland. Platanthera chlorantha (Greater Butterfly-orchid) In the vegetative state it might possibly be mistaken for Neottia ovata Twayblade but when flowering, it Records not found 1 Records <2000 can only be confused with Platanthera bifolia Lesser Butterfly-orchid. The distinguishing feature is the Records 2000-2009 position of the two pollinia, relative to each other. In P. chlorantha they are widely separated at the base Records 2010-2019 but lean inwards at their tips to almost touch, whilst in P. bifolia they are parallel. SO SP Records >=2020
P. chlorantha is not at all scarce in VC8 where it is found, in particular, in three large woodland blocks, Great Ridge, Grovely and Bentley. Individual records for the plant have doubled in this millennium 9 compared to the 1984-2000 period. The situation in VC7 is very different; here both the number of records and the number of squares from which it has been recorded have dropped by about half over 8 the same period of time. The plant appears to have been less frequent in VC7 for a considerable length of time and it is 7 most often found in the Braydon Forest area and on the edge of the Cotswolds. 6 In considering a new county flora, it would therefore be important to know whether 5 the apparent decline in VC7 is a valid one. Given the data from VC8, Climate Change cannot be blamed but is habitat loss a 4 significant contributor?
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1 ST 78 9 SU 1 2 3 4 Vicia sylvatica Wood Vetch
A species that has always been localised in Wiltshire. It is unusual in that it has a very long history at many of its locations, but may disappear and reappear periodically. It tends to reappear when areas of woodland have been cleared, especially at their fringes and boundaries.
Its existance seems to be quite stable, with 77 records between 1980 and 1999, and 73 between 2000 and 2019. However, later records are often multiple repeats at fewer sites, for instance in Vicia sylvatica (Wood Vetch) Clouts Wood or Collingbourne Wood. Records not found 1 Records <2000 Vicia sylvatica can grow to a big plant, up to 2m in height. Its tendrils are branched, with characteristic Records 2000-2009 spiky, crown-like stipules. It ramps and climbs over vegetation and is hard to miss if it’s there. It has a Records 2010-2019 Records >=2020 long flowering period, or at least is evident for most of the season from May onwards. SO SP
It seems to be tolerant of many soils but is most frequent on Greensand fringing the Chalk, and the Clay-with Flint of 9 West Woods.
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1 ST 78 9 SU 1 2 3 4 GRASSLAND Clinopodium acinos Basil Thyme Clinopodium acinos (Basil Thyme)
An annual plant of sunny calcareous grasslands and disturbed areas, including arable land. Its Records not found 1 Records <2000 stronghold is on Salisbury Plain where military vehicles disturb the ground and allow it to Records 2000-2009 proliferate. At an international level it is regarded as IUCN Vulnerable, adding greater Records 2010-2019 significance to our Wiltshire populations. SO SP Records >=2020 In good conditions the plant can grow to a height of perhaps 25 cm although it often has a more sprawling habit. The flowers are coloured violet /purple with white markings. It is 9 separated from other members of the genus by its tight, axillary whorls of 3 – 8 flowers. There is a useful key to Clinopodium in the Collins Flower Guide by Streeter et al. 2009.
The number of records of the species in VC8 has increased by over 100% since 2000, (186 8 rising to 457) the majority of these coming from SPTA. In sharp contrast, the number of records in VC7 has 7 decreased from 22 pre-millennium to just once since 2000 and we therefore feel that it is important to search for 6 this plant and to establish whether or not these figures represent the true picture. 5
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1 ST 78 9 SU 1 2 3 4 Ononis spinosa Spiny Restharrow
A woody perennial to 45cm of nutrient poor, calcareous soils such as chalk, coral rag limestone and heavy calcareous clay of rough grassland. In VC8 the numbers of records received have Ononis spinosa (Spiny Restharrow) remained stable over the years (96 pre-2000 to 99 up to 2020) however in VC7 they are receding Records not found 1 (189 pre-2000 to 132 up to 2020). Even the Wiltshire Flora reported…’h as disappeared from the Records <2000 north-east where it was once frequent, due to agricultural intensification’… Records 2000-2009 Records 2010-2019 It can be confused with its very similar cousin Ononis repens Common Restharrow. It is not SO SP Records >=2020 enough just to feel for spines as sometimes O. spinosa can have small amounts and O. repens can sometimes have a few! 9 O. spinosa ...... Ascending to erect, not rhizomatous. Young shoots are hairy on one, or two opposing sides. Leaflets >3x as long as wide.
O. repens ...... Procumbent to ascending, rhizomatous. Young shoots hairy all round. Leaflets 8 <3x as long as wide.
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1 ST 78 9 SU 12 3 4 Ophioglossum vulgatum Adder’s-tongue
A native of damp grass land; diminutive in stature and can be ‘difficult’ to see until you get your eye in. Adder’s-tongue is a bellwether species of unimproved grassland; most frequent on neutral heavier clay and clays overlaying Limestone, alkaline gravels and occasionally chalk, that stay damp for much of the year. It avoids acid soils.
Although mostly known from unimproved meadows it also occurs in woodland rides quite Ophioglossum vulgatum (Adder's-tongue) frequently. Recording of this species has declined, possibly because of its diminutive size and its Records not found ability to grow in very diverse grassy habitats that make it a difficult to see. There is a good chance 1 Records <2000 we are just missing it. It often has a very long history in any one location but maybe other sites are Records 2000-2009 just not being visited or the Records 2010-2019 Records >=2020 plant looked for at the right SO SP time?
It starts to appear in very late 9 April and can be found right through to the hay cuts of July; later if cutting is delayed. 8
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1 ST 78 9 SU 1 2 3 4 WATER Hydrocotyle vulgaris Marsh Pennywort
Always rare in Wiltshire, largely due to its habitat preferences. Typically found in marshes and bogs, its Wiltshire headquarters are in the Cotswolds Water Park and the limited parts of the New Forest which are in VC8. Since 2000, it has only been recorded from three 1 km squares in VC7 and 17 1km squares in VC8. It is much more common over the borders into Hampshire and Dorset.
Its flowers are small and hard to spot, however the leaves are distinctive: circular with shallow teeth Hydrocotyle vulgaris (Marsh Pennywort) (1-5 cm wide) with stems attached to the leaf centres (like little parasols). Creeping and prostate, it forms Records not found mats in suitable habitats. 1 Records <2000 Records 2000-2009 Not to be confused with the America invader Hydrocotyle ranunculoides , which is found in still or slow- Records 2010-2019 SO SP Records >=2020 moving rivers and ditches, and whose stems join the leaf edges. Both are worth recording, for very different reasons. 9
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1 ST 78 9 SU 1 2 3 4 Oenanthe fistulosa Tubular Water-dropwort
Flowering from July onwards in damp or wet places usually subject to winter flooding. An indicator of high -quality wet meadows and pastures, in Wiltshire it's mostly found near the Cotswold Water Park (Clattinger Farm, North Meadow, etc.) and in the Salisbury water meadows. Re-finds in the Kennet valley have been rare in recent years, suggesting targeted searches could be fruitful. Abandoned stretches of canal or their back -waters may be worth searching. Something appears to be happening in VC8, with 1km square records dropping from 20 to 7 since 2000. Oenanthe fistulosa (Tubular Water-dropwort) Vegetatively it displays the classic pinnate leaves (once or twice) of umbellifers. The stems are hollow Records not found 1 and swollen between leaf junctions. The umbels are bractless (but bracteoles are present) and form Records <2000 Records 2000-2009 striking dense white balls, two to four at around 1 cm across . Records 2010-2019 Records >=2020 Weird spiky heads in fruit SO SP
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Text and photos from Dave Green, Pat Woodruffe, Martin Buckland, Steve Beal 1 Extra photos: Richard Aisbitt and Malcolm Storey (Ononis , from www.bioimages.org.uk ) ST 78 9 SU 12 3 4