THE BOTANY OF PLYMOUTH. 
389 
porting a great variety of varied forms that delight to grow in 
proximity to running fresh-water, or need a damp soil, whilst the 
adjoining meadows or overhanging woods supply all required hy 
numerous pratal or sylvestral species. Further north are large 
commons to yield ericetal plants, or such as are only found where 
virgin turf still prevails. Here, too, are extensive moory tracts, 
where abundant moisture on the surface and in the atmosphere 
nourishes numerous beds of Sphagnum, to support, either in decay 
or when in verdure, the requirements of several uliginal plants, 
such as the Droserce, Pinguecula lusitanica, &c. A few others of 
another nature find in the clefts of the adjacent tors, or on the 
many rocky declivities, all that they need. On the other hand, our 
Flora is poor with regard to one class of plants — fresh-water 
aquatics — to be accounted for from the fact of sluggish streams and 
still waters being not numerous in so hilly a tract. Moreover, it 
has not the canals (at least, in any number) that afford in many 
districts all that several of such species require. Thus do we find 
on all sides an intimate connection between the physical features 
and the botany of the country around Plymouth, and see surface 
peculiarities furnishing reasons for facts connected with floral 
distribution 
Some reference was made to the agriculture of the area, also to 
its lanes and hedge-banks. 
A sketch of its whole system of drainage, together with the 
names, boundaries, and botanical peculiarities of six districts 
founded on it, was given, followed by particulars respecting its 
geology, and an attempt to trace in a small measure the influence 
of geological and lithologieal phenomena on its botany, the 
lecturer being willing to attribute quite as much power to the 
lithologieal character of a rock as to its chemical composition. 
Facts respecting the climate of Plymouth were then stated, and 
the probability was suggested of its influencing the floral features 
of the area more by its general equability and its humidity than 
in any other way. 
Two other matters that bear on the relative distribution of species 
were then mentioned — the warfare between species, and insect agency. 
In conclusion, the lecturer observed that, although diverse and 
difficult to discover were the laws and influences that had produced 
the existing Flora of Plymouth, yet that they together had been 
powerful was proved by the large number of its species. Scattered 
