70 
Perhaps the most variable species is the widely-distributed 
E. Centaurium, Pers., as the specimens exhibited will show. 
Its most usual form is that in which the stems, whether 
solitary or several springing from the crown of the root, 
branch in the upper third of their height, the branches 
terminating in one or more dense heads. A second form, 
less common than the first, bears numerous branches from 
the base to the summit, its terminal cymes having a spicate 
direction. A third form, which I meet with on the Lanca- 
shire coast sandhills, has a solitary slender stem terminated 
in its upper eighth by one to three few-flowered contracted 
cymes ; the habitat in which it usually occurs is at the base 
of the sandhills at the edges of the flat damp hollows in 
which Erythrwa littoralis is so abundant. It varies in 
height from 6 to 18 inches, and the leaves of the lower 
fourth of the stem are obtuse, obovate, and at times even 
spathulate. Its habit suggests its being a hybrid between 
E. Centaurium and E . littoralis ; but its characters range 
with E. Centaurium. At the opposite extreme is a fourth 
form, also maritime, which is met with growing amongst 
the grass of exposed cliffs and sea-slopes. It is a stunted 
form with spreading capitate heads, whose breadth often 
exceeds the entire height of the plant. Its height is usually 
determined by that of the contiguous herbage, and when it 
can secure the shelter of tall plants its stem elongates and 
branches in the upper haif. This form is the var. capitata 
of Koch, and the pseudo-latifolia of the London Catalogue. 
I have not observed it away from the western coast, 
although I have seen on Afton Downs, in the Isle of 
Wight, plants with more contracted and fewer- flowered 
