Cambridge Group: Longstowe Hall, Home and Bourn Woods

HomeEventsCambridge Group: Longstowe Hall, Home and Bourn Woods

19 March 2023

Meeting report

Present: Jonathan Graham, Mark Hill, Nick Jardine, Nick Millar, Monica O’Donnell, Chris Preston, Jonathan Shanklin.

We met at Longstowe Hall at the time of year when the bryophytes are at their best and on a day when they were wetted by overnight rain – ideal conditions for bryology. With the exception of a single record of Homalia trichomanoides by E.F. Warburg and T.G. Tutin in 1929, our records from Longstowe Hall and its adjacent woods start in the 1940s. They were visited several times in that decade, probably because it was a short walk from the former Old North Road railway station. We held excursions here in 1978, 1983 and 2004. This time we were very grateful to Mr William Bevan for permission to visit and Vasile Boz for facilitating access on the day.

We started off at the Hall. Like many such sites, the grounds receive much more attention than was perhaps the case on our earlier visits as they are now a major venue for weddings. We started at the stone balustrade near the house. In 2004 we saw Seligeria calcarea on fallen small lumps of stone, and Thuidium assimile in the turf nearby. Remarkably, the Seligeria was still present on one fallen flake of stone (we thought that the stone was oolitic limestone in 2004 but I don’t now think that it is). We could not see any Thuidium in this area, and it may be that the lawn is now more intensively managed.

Seligeria calcarea on a flake of stonework

We found a good number of other saxicolous species, then walked down to the lake. As often in parkland we recorded a wide range of species although none of them was particularly rare. They included Cratoneuron filicinum, Didymodon sinuosus and Rhynchostegium riparioides on stonework by the weirs (but we could not refind Fontinalis). Mark spotted Microeurhynchium pumilum on a stream bank below the lake, the first record since Michael Proctor’s in 1951. When Mark found Pulvigera lyellii on a tree by the lake, just before lunch, it took the total of species on the card to 50. This seemed a high total for v.c. 29 but as we have usually recorded more than one site by 12.30 we don’t normally calculate the lunch-time score.

In the afternoon we recorded Home Wood and Bourn Wood, separately, and Longstowe churchyard. A Roman Road (Ermine Street) runs between the woods and this was the site of a notorious murder, by highwaymen, c. 1280, which led to the practice of clearing strips of woodland alongside major roads. We thought that both woods looked as if they had been elm woods which had been much altered since Elm Disease and after our visit I was able to confirm this from Oliver Rackham’s notebooks, many of which can be consulted on-line in the Cambridge University Library’s Digital Library. Oliver recorded elm as the main tree species in the 1960s, with dense populations of oxlips. In 1972 he noted one elm infected in a hedge in Longstowe. Bourn Wood was felled in the 1981/82 winter after its elms had succumbed to disease, giving a magnificent display of oxlips in 1982, but the oxlips had declined by 1986 and we only noticed a few groups in each wood.

We found a reasonable selection of woodland bryophytes in Home Wood. I got detached from the group at one point and found a felt of Platygyrium repens, fallen from the branch of an oak tree, Homalia frequent on one ash base and a single tuft of Lewinskya striata on ash. Jonathan G added Isothecium myosuroides on ash. Several very old and sometimes fragmentary oak stumps had calcifuges including a few stems of Dicranum tauricum, much Mnium hornum and some Orthodontium lineare. These are presumably the remains of the very large stumps Oliver saw in 1967, after the recent felling of oaks in this wood (leaving elm as the dominant species). There were fine patches of Plagiomnium rostratum on soil by the drive through the wood to the Hall.

Lewinskya striata on Oak

Frullania dilatata on a gravestone

On our visit in 2004 we noted that Bourn Wood had been replanted with native species. This is still the case, though the rows of very straight, pale barked ash looked like a single genotype selected by foresters. Our list here was less extensive than that at Home Wood but we did add Atrichum undulatum and Orthotrichum pulchellum to the day’s list.

In the churchyard we recorded 29 species, adding six to the 30 already recorded. Cirriphyllum piliferum and Thuidium tamariscinum grew in the turf and Neckera complanata was found by Jonathan G on limestone at the base of the church wall. Neckera has not been seen in the woods here since 1944. Another notable habitat record was of Frullania dilatata. Jonathan S found intensely purple plants on a flat gravestone at the E end of the church; we counted eight patches and at least one of them (checked by Mark just to make sure it was F. dilatata) was male.

In all we recorded 75 species in a very enjoyable day’s bryology. As it is clear that the earlier recorders did not always distinguished the park and woods are carefully as we do, I’ve lumped all the records except those from the churchyard together to look at the evidence for change in these sites.

Species recorded previously and refound: 50 (of which 47 had been seen in 2004). Of these 50, 43 had been seen more than once on the past and 7 only once.

Species newly recorded from the site:  21.

Species seen previously but not refound: 42 (of which 5 were last seen before 1950, 14 in 1978 or 1983 and 23 in 2004). Of these 42, 19 had been seen more than once in the past and 23 only once.

As expected, over half the additions (11 species) were epiphytes; the epiphyte flora was evidently still fairly poor in 2004. We also added Orthotrichum anomalum, O. cupulatum and Zygodon viridissimus on stonework. Other additions included the spreading Syntrichia ruraliformis, two calcifuges, Dicranum tauricum and Isothecium myosuroides, and the inconspicuous Brachythecium mildeanum.

The species we failed to refind comprised a range of ecological groups, including the woodland species Anomodon viticulosus (last seen 1949), Chiloscyphus pallescens (1978), Hylocomiadelphus triquetrus (1944), Plagiochila asplenioides (2004) and Porella platyphylla (1944) and a suite of calcifuges, including Aulacomnium androgynum (1978), Dicranella heteromalla (1983), Dicranoweisia cirrata (2004), Dicranum scoparium (1978), Pohlia nutans (1983) and Polytrichum juniperinum (2004, on a stump). These fit with general trends in the bryophytes of the county. There is a large group of ephemerals on the missing list, some previously recorded from the Hall including Bryum klinggraeffii (1983), B. ruderale (2004), Tortula acaulon (2004), some from the wood, Dicranella staphylina (2004), Ephemerum serratum (2004) and Pohlia wahlenbergii (1983), and some from both, Dicranella schreberiana (1983), Funaria hygrometrica (2004) and Tortula truncata (2004). Our failure to refind these must reflect more site-specific factors – less disturbance in the woods currently and perhaps the extremely scrupulous weeding of the rose garden by the Hall. Maybe we just overlooked inconspicuous species on stonework such as Didymodon umbrosus (2004), Gyroweisia tenuis (1983) and Tortula marginata (1983). The species recorded most frequently in the past which we failed to refind were Pellia endiviifolia, which we certainly looked for, and the declining Dicranoweisia cirrata, each with six earlier records. No doubt with further searching many of the species recorded in 2004, and some of the others, could be refound at this large and varied site.

Chris Preston, 20 March 2023