Chapter IV: Flora and Fauna

In his _Cybele Britannica_, H. C. Watson divided Britain into eighteen botanical provinces of which the Thames and the Ouse occupy the whole of the S.E. of England. The greater part of Hertfordshire is in the Thames province and a small portion in the N. is in that of the Ouse.

In Pryor's _Flora of Hertfordshire_, published by the Hertfordshire Natural History Society in 1887, which should be referred to for full information on the botany of the county, these botanical provinces are again divided into districts, the Ouse into (1) Cam, (2) Ivel; and the Thames into (3) Thame, (4) Colne, (5) Brent, (6) Lea; both the larger provinces and the smaller districts thus being founded on the natural divisions of a country, drainage areas or catchment basins.

In the following brief notes a few of the rarer or more interesting flowering plants of each district are enumerated.

1. _The Cam._--This is the most northern district. It is almost entirely on the Chalk and is very bare of trees. The few plants which are restricted to it are very rare. A meadow-rue, _Thalictrum Jacquinianum_, and the cat's foot (_Antennaria dioica_) occur only on Royston and Therfield Heaths; _Alisma ranunculoides_ and _Potamogeton coloratus_ only on Ashwell Common; and of the great burnet (_Poterium officinale_) the sole record is that of a plant gathered near Ashwell in 1840.

2. _The Ivel._--This district is S.W. of that of the Cam, and the Chalk Downs of that district are continued through it. Its rarer plants are _Melampyrum arvense_, which occurs only in one spot S. of Ashwell; _Smyrnium olusatrum_, which has been found near Baldock and Pirton; and _Silene conica_, which was found near Hitchin in 1875. The white helleborine (_Cephalanthera pallens_), the dwarf orchis (_Orchis ustulata_), and the musk orchis (_Herminium monorchis_) occur on the Chalk Downs.

3. _The Thame._--A very small tongue-like protrusion[a] of the extreme W. of the county, in which are the Tring Reservoirs. Two of the species confined to the district, _Typha angustifolia_ and _Potamogeton Friesii_, are water-plants which occur only in these reservoirs or in the canals which they supply. A rare poplar, _Populus canescens_, grows by the Wilstone reservoir, and the man-orchis (_Aceras anthropophora_) on terraces cut in the Chalk near Tring.

4. _The Colne._--A large district, comprising almost the whole of the western portion of the county. _Diplotaxis tenuefolia_, _Silene nutans_, and _Hieracium murorum_ grow only on old walls in St. Albans. Colney Heath is our only habitat for a very rare loosestrife, _Lythrum hyssopyfolium_, and also for _Teesdalia nudicaulis_, while there is but one other locality, a different one in each case, for four of its plants, _Radiola linoides_, _Centunculus minimus_, _Cuscuta epithymum_, and _Potamogeton acutifolius_. The pasque-flower (_Anemone pulsatilla_) grows abundantly on the Chalk slopes near Aldbury. The rarer orchids of the district are the bog-orchis (_Malaxis paludosa_), the narrow-leaved helleborine (_Cephalanthera ensifolia_), and the butterfly orchis (_Habenaria bifolia_).

5. _The Brent._--The smallest district, a protrusion[b] of the county in the S. entirely on the London Clay, and chiefly interesting owing to the presence of Totteridge Green and its ponds. In these ponds grow the great spearwort (_Ranunculus lingua_) and the sweet-flag (_Acorus calamus_), the former, however, not being indigenous. The star-fruit (_Damasonium stellatum_) formerly grew on Totteridge Green, and _Chenopodium glaucum_ at Totteridge, but neither has lately been seen.

6. _The Lea._--The largest district, comprising the whole of the E. of the county. The London rocket (_Sisymbrium irio_) occurs only in the old towns of Hertford and Ware; the true oxlip (_Primula elatior_) near the head of the River Stort; a very rare broom-rape, _Orobanche cærulea_, at Hoddesdon, where it is parasitic on the milfoil; and an almost equally rare bedstraw, _Galium anglicum_, on an old wall of Brocket Park. A rare trefoil, _Trifolium glomeratum_, is known only at Easneye near Ware; and Hatfield Park is our only locality for the water-soldier (_Stratiotes aloides_) except where it has evidently been planted. Two species, usually of rare occurrence, _Polygonum dumetorum_ and _Apera spica-venta_, are frequent in the district.

The indigenous flowering plants of Hertfordshire number 893 species, 679 being Dicotyledons and 214 Monocotyledons. If to these be added 199 aliens, etc., the total number of species recorded is brought up to 1,092. The flora is essentially of a southern type, the northern species being few in number. Owing to the dry soil, xerophiles largely prevail over hygrophiles.

_The Ferns_ and their allies the horsetails and clubmosses are not well represented, both the soil and the air of the county being too dry for them. Another cause for the present scarcity of ferns is the proximity of Hertfordshire to London, for they have been uprooted and taken there for sale in cart-loads. We have twenty-four species of ferns and fern-allies, but not one really rare. The principal varieties are _Scolopendrium vulgare_, var. _multifidum_; _Athyrium filixfæmina_[c], var. _convexum_; and _Polypodium vulgare_, var. _serratum_. _Equisetum silvaticum_ is our rarest horsetail; and our only clubmoss is _Lycopodium clavatum_.

_The Mosses_ are much better represented than the ferns, 175 species having been recorded. The bog-mosses are represented by six species--_Sphagnum intermedium_, _cuspidatum_, _subsecundum, acutifolium_, _squarrosum_, and _cymbifolium_. _Tetraphis pellucida_ occurs in Sherrard's Park Wood, and _Polytrichum urnigerum_ in Hitch Wood. _Seligeria pusilla_ has been found in an old chalk-pit in Brocket Park, and _S. paucifolia_ on chalk nodules in the Tunnel Woods near Watford. _Campylopus pyriforme_ occurs in Berry Grove Wood, Aldenham, and _C. flexuosus_ in Dawley's Wood, Tewin.

Of _the Liverworts_ (_Hepaticæ_) forty-four species are known to occur; and the Stoneworts (_Characeæ_) are represented by seven species--two of _Chara_, two of _Tolypella_, and three of _Nitella_.

_The Algæ_ have been pretty fully investigated, especially the _Diatomaceæ_, of the 252 species of Algæ known to occur in the county, 156 belonging to that interesting family of microscopic plants. As an illustration of their minute size it may be mentioned that a single drop of water from the saucer of a flower-pot at Hertford, mounted as a microscopic slide, was found to contain 200,000 separate frustules of _Achnanthes subsessilis_, and it was estimated that these occupied only one twenty-fifth part of the drop. Both species of _Chlamidococcus_ (the old genus _Protococcus_), _C. pluvialis_ and _C. nivalis_ occur; and the pretty _Volvox globator_ has frequently been found.

Of _the Lichens_ much less is known, only sixty-seven species having been recorded. The most noteworthy are _Calicium melanophæum_, found on fir-trees in Bricket Wood; _Peltigera polydactyla_, on moss-covered ground in Oxhey Woods, Watford; _Lecanora phlogina_, in the Tunnel Woods, Watford; and _Pertusaria globulifera_, on trees in the same woods and also in Bricket Wood. As woods in the vicinity of Hertford and of Watford only have been searched for lichens, our list ought to be largely increased by investigation in other parts of the county.

Of _the Fungi_ our chief knowledge is derived from lists of species collected at Fungus Forays of the Hertfordshire Natural History Society and from records of the Mycetozoa by Mr. James Saunders. The number of species recorded for the county is 735, of which fifty-eight are "myxies". Of the Hymenomycetes, or mushroom-like fungi, some very noteworthy finds have been made, nearly all at Forays of the county society. They include two species new to Britain, _viz._, _Agaricus (Nolania) nigripes_, found in Aldenham Woods, Watford, and _Ag. (Hypholoma) violacea-ater_, in Gorhambury Park, St. Albans (by the present writer). Hertfordshire has also furnished the second British records for _Ag. (Lepiota) gliodermus_ (Broxbourne Woods), _Ag. (Leptonia) euochrous_ (Ashridge Woods), _Ag. (Psathyrella) aratus_ (Sherrard's Park, Welwyn), and _Paxillus Alexandri_ (Hatfield Park), this species having first been recorded from Hatfield Park, Essex; and the second and third British record for _Agaricus (Clytocybe) Sadleri_ (Ashridge Park and Cassiobury Park). The very rare _Strombilomyces strombilaceus_ has been found in Grove Park, Watford, and the still rarer _Peziza luteo-nitens_ on the Chalk slopes between Aldbury and Ashridge Park. Lastly it may be mentioned that Mr. Saunders added the "myxie" _Physarum citrinum_ to the British fungus-flora from specimens found by him at Caddington and Welwyn.

_The Birds_ of Hertfordshire have been carefully observed, and the appearance of rare visitors has been duly recorded. At a lecture delivered at St. Albans in 1902, Mr. Alan F. Crossman, F.L.S., F.Z.S., stated that 212 species had been known to visit the county, and mentioned, _inter alia_, that the kingfisher is more numerous in Hertfordshire than formerly, that the heron nested in the county for the first time in 1901, and that the appearance of the bearded titmouse had been noticed on but three occasions. During the last forty years the following birds, among others, have been noticed as occasional visitants: the storm-petrel (_Procellaria pelagica_), golden oriole (_Oriolus galbula_), whooper-swan (_Cygnus musicus_), snow-bunting (_Plectrophanes nivalis_), greater spotted woodpecker (_Picus major_), black tern (_Hydrochelidon nigra_), great northern diver (_Colymbus glacialis_), herring-gull (_Larus argentatus_), cormorant (_Phalacrocorax carbo_), tufted duck (_Fuligula cristata_), hoopoe (_Upopa epops_), crossbill (_Loxia curvirostra_), sheldrake (_Tadorna cornuta_), Guillemot[d] (_Lornvia troile_), Pallas' sandgrouse (_Syrrhaptes paradoxus_), rock thrush (_Monticola saxatilis_), black redstart (_Ruticilla titys_), Dartford warbler (_Silvia undata_), grasshopper warbler (_Locustella nævia_)[d], waxwing (_Ampelis garrulus_), twite (_Linota flavirostris_), hen harrier (_Circus cyaneus_), buzzard (_Buteo vulgaris_), redshank (_Totanus calidris_), greenshank (_Totanus cunescens_) and the little auk (_Mergulus alle_).

The lapwing is thought to be increasing in numbers; the writer frequently observed considerable flocks during his recent rambles in the county. Finches are perhaps as numerous in Hertfordshire as in any other county of equal size; the large flocks of hen chaffinches that haunt the farmyards in winter being quite a notable feature. The goldfinch, it is to be feared, is rapidly becoming scarcer; as are also the jay, the woodcock and other birds much more numerous a few years back. Fieldfares and redwings visit the county in great numbers from the N. during the winter; one morning in the winter of 1886 the writer saw many thousands of fieldfares pass over St. Albans from the direction of Luton. The redwing, being largely insectivorous, is often picked up dead in the fields when the frost is unusually severe and food proportionally difficult to obtain.

The presence of many woods and small streams attracts a good proportion of the smaller English migrants; the nightingale and the cuckoo are heard almost throughout the county. Moorhens, coots and dabchicks are abundant; the reed-sparrow is heard only in a few districts. Titmice, great, blue and long-tailed, are well distributed.