Pills, Pools and Marshes - Gower - page 228

sink, flowing through caves along joints and bedding planes in the limestone before reappearing above
groundasasurfacestreaminthelowerpartoftheBishopstonValley,meetingtheseaattheshinglebeach
in Pwlldu Bay.
FLORA AND FAUNA
There is a varied flora in and alongside the various streams, brooklime Veronica beccabunga being par-
ticularlycommon,whilepinkwater-speedwell Veronica catenata islocallyfrequentonwesternGowerin
shallowstreamsoncalcareoussoils.Inwatercoursesneartheseaamphibiousbistort Polygonum amphibi-
um is often found.
On the banks hemlock water-dropwort Oenanthe crocata and yellow loosestrife Lysimachia vulgaris
occur along with a wide variety of plants including blinks Montia fontana , marsh-marigold Caltha palus-
tris (Fig. 129), winter-cress Barbarea vulgaris , lesser spearwort Ranunculus flammula , lesser water-
parsnip Berula erecta and great willow herb Epilobium hirsutum . Where streams cross acid soils hard
fern Blechnum spicant is common. Most of the invasive, non-native streamside plants such as monkey-
flower Mimulus guttatus , although widely naturalised elsewhere in Glamorgan, are still scarce and local
inGower.TheexceptionisJapaneseknotweed,whichisspreadingrapidlyalongthestreams,asdescribed
in Chapter 7.
FIG 129. Marsh marigold, a common plant of the Gower streams and marshes. (Harold Grenfell)
There is little information available on the species of fish in the Gower streams and their distribution,
mainly because there is very little angling interest in the freshwater habitats. More research is needed, but
species known to occur, apart from the ubiquitous three-spined stickleback Gasterosteus aculeatus , in-
clude ten-spined stickleback Pungitius pungitius , roach Rutilus rutilus , perch Perca fluviatilis and brown
trout Salmo trutta .Somefishofinshorewaters,suchasthick-lippedgreymullet Mugil labrosus ,flounder