Genus Statice as represented at Blakeney Point. I. 261 
to cortex is markedly different in the two cases. Culture appears to have 
had the effect of increasing the width of the phloem zone (chiefly by the 
production of phloem parenchyma), of greatly increasing the amount of 
cortical parenchyma, and markedly decreasing the proportion of scleren- 
chymatous fibres present, i. e. culture has considerably reduced the production 
of incompressibility in the root. Moreover, while parenchyma cells are 
entirely absent in the xylem of the type plant, in the root of the culture 
plant the wood is composed of vessels, xylem parenchyma, and very 
few fibres. 
To a much less extent the roots growing in the muddy and sandy-mud 
lows also show a diminution in the proportion of sclerenchyma and 
sclereide present in the cortex. 
Text-fig. 12 . A = diagram of the transverse section of the root of a Main bank plant of 
S. binervosa ; B = diagram of the transverse section of a root of a plant of S. binervosa cultivated in 
garden soil from seed, x 50. xy. = secondary xylem ;///.= secondary phloem ; s.f = sclerenchyma 
fibres ; />. = cortical parenchyma ; fer. — periderm. 
Observations which are of some interest in this connexion have been 
made by van Ufford during the course of his investigation of the Flora of 
the Pierriers ( Moraine talus) of the High Calcareous Alps of the Canton de 
Vaud. 1 
The most striking feature in the anatomy of these plants was the 
development of collenchyma in the peripheral regions of the underground 
axes. Pie regards this collenchyma as acting in resisting the thrust of the 
mobile stones while at the same time permitting without rupture the neces- 
sary stretching needed on account of the mobility of the substratum. In the 
case of .S. binervosa , since there is no need to provide a mechanical tissue 
which will allow of further growth in the organ, as the substratum is not 
mobile, the collenchyma is replaced by the mechanically more efficient 
sclereides. 
Examining the relations between the thickness of the collenchyma and 
1 van Ufford, Q. : Etudes ecologiques de la flore des Pierriers. These. Montreux, 1909. 
T 
