The district around Helensburgh, extending from Bowling Bay to Roseneath, abounds with the commoner plants, including some rare species. At Bowling, Turritis glabra occurs, along with the rare moss, Glyphomitrium Daviesii, found in 1842 and 1863. On Dumbarton Castle rock the following plants abound:—Smyrnium olusatrum, Carduus marianus, Malva sylvestris, M. moschata, Conium maculatum, Carex muricata, Poa maritima. Along the banks of the Clyde, Mimulus luteus is of frequent occurrence; it is a native of Chili, and has become naturalised within the last twenty years in different parts of Scotland. The most characteristic plant in the neighbourhood of Helensburgh, and on the banks of Gareloch, especially at the upper extremity, near Ferny-carry, is Bartsia (Trixago) viscosa, a rare species in other parts of the country, but remarkably abundant here. Senecio saracenicus has been observed at the east end of Helensburgh, but was probably an escape from a garden. It has long been known to occupy a spot at Bothwell Bridge. Carum verticillatum, a rare plant in England, is common in the moist pastures and salt marshes from Bowling to Helensburgh. Lythrum salicaria grows in profusion in the marshes in the neighbourhood. Epilobium hirsutum is found in the vicinity of Helensburgh; Valeriana Pyrenaica on the sides of a stream in the Roseneath woods; Trollius Europaeus at Gareloch-head; Convolvulus sepium on the shores of the loch; Sedum anglicum and S. acre on Dumbuck and in many other places, and S. Telephium is not infrequent; Saxifraga aizoides beside the upland streams, as at Glen Fruin; Solanum Dulcamara in the hedges west of Helensburgh; Linum catharticum in all the fields. Amongst other species more or less frequent, are the following—

Anemone nemorosa
Corydalis claviculata
Arabis hirsuta
Cardamine amara
Cochlearia officinalis
Draba verna 
Lepidium Smithii
Parnassia palustris
Silene maritima
Vicia hirsuta
Rubus saxatilis 
Circaea alpina ——
——Lutetiana
Montia fontana
Chrysosplenium alternifolium ——
——oppositifolium
Daucus carota
Oenanthe crocata
Sanicula
Europaea
Adoxa moschatellina
Lonicera
Periclymenum
Aster
Tripoliun
Eupatorium cannabinum
Sonchus oleraceus
Vaccinium
Myrtillus ——
——Vitis-Idaea ——
——Oxycoccos
Gentiana campestris
Anchusa sempervirens
Melampyrum pratense
Veronica anagallis ——
——scutellata
In Ardenconnel Glen,
Stellaria
Holostea Hypericum Androsaemum ——
——humifusum ——
——perforatum ——
——pulchrum ——
——quadrangulum
Geranium pratense
Oxalis acetosella
Prunus communis (spinosa)
Galeopsis
Tetrahit ——
——versicolor
Lycopus
Europaeus
Scutellaria galericulata
Pingnicula vulgaris
Anagallis arvensis ——
——tenella
Glaux maritima
Lysimachia nemorum
Plantago maritima
Chenopodium album
Salsola
Kali
Epipactis latifolia
Gymnadenia conopsea
Habenaria viridis
Orcbis latifolia ——
——maculata ——
——mascula
Agraphis nutans
Triglochin maritimum ——
——palustre
Zostera marina.
 Hymenophyllum Wilsoni occurs amongst the ferns, the commoner species of which are abundant in the woods and valleys, viz.:—
Asplenium
Adiantum nigrum
Lastrea dilitata ——
——Trichomanes
Polypodium vulgare ——
——Filix-foemina ——
——Phegopteris
Blechnum boreale ——
——Dryopteris
Cystopteris fragilis
Polystichum lobatum
Lastrea
Filix-mas
Scolopendrium vulgare. ——
——Oreopteris
The two silver firs in Roseneath woods are interesting botanical objects, each measuring about nineteen feet in circumference. The Robinia Pseudo-acacia thrives indifferently in most parts of Scotland, but accommodates itself to the climate of this neighbourhood, where it flowers. The Wellingtonia gigantea (the mammoth tree of California) is also hardy in this quarter. As a proof of the mildness of the climate, it may be mentioned that in the memorable frost of December 1860—the most severe experienced in the present century—the Arancarius, Deodars, the Laurustinus, the Rhododendrons, and Laurels remained uninjured, although without protection, when plants of the same description perished almost universally in the upper parts of the Clyde valley, and in the interior of the country generally.