499 
Stomata in Halophytes . 
Withering shoots of Suaeda and of Sedum album present a further 
point of similarity, since in both the old leaves act as water reservoirs for 
the young leaves at the growing apex. However, in Sedum each oldest 
leaf in turn yields up its water and shrivels ; 1 just before shrivelling a single 
short white rootlet appears, standing just above the insertion of the leaf at 
right angles to the stem which bears it. During such withering the youngest 
leaves appear not to suffer in the least from want of water, and the rate of 
transpiration is maintained almost unimpaired for as long as five or six 
weeks. In Suaeda , on the other hand, no such rootlets were seen, and the 
old leaves withered several together, whilst the young leaves were per- 
ceptibly flaccid, although much less so than the oldest ones. Stiaeda will 
withstand desiccation for one week, Sedum for as long as six weeks. 
The foregoing experiments, although scattered over different seasons 
and performed under different physical conditions, present, when taken 
together, sufficient evidence to show that the transpiration of at least some 
typical halophytes is by no means as reduced in character as has been 
frequently asserted. 
There is indeed little or no cuticle in Saticornia , in Suaeda maritima , 
and probably also in some other halophytes. This renders a considerable 
water loss inevitable, in spite of the frequently closed stomata 2 and the 
acidity 3 of the cell-sap in the green parts. This is compensated partly by 
the storage of water in the aqueous tissue and partly by the power which 
these plants possess of absorbing water over their green surface, a power 
which must be of much value in the damp and yet often exposed situations 
in which they are frequently found. 
IV. Behaviour of the Stomata in Halophytes. 
The behaviour of the stomata in halophytes was subjected to investi- 
gation by Stahl 4 in 1894, and by Rosenberg 5 in 1897, in both cases chiefly 
by means of the cobalt paper test. 
Stahl found in this way that the stomata of certain halophytes which 
he had cultivated in an artificial salt marsh were constantly more or less 
widely open. He concluded that halophytes resembled freshwater marsh 
plants in possessing stomata which had lost the power to close. 
Rosenberg applied the same method to the leaves of halophytes im- 
mediately after they had been detached from the plant growing in situ. 
In all the cases examined by him the stomata, open at first, closed shortly 
1 Cp. Pringsheim, E. (’06) : Wasserbewegung und Turgorregulation in welkenden Pflanzen. 
2 Cp. Rosenberg, O. (’97) : Ueber die Transpiration der Halophyten. 
3 Aubert, E. (’92) : Turgescence et transpiration des plantes grasses. Ann. des Sci. Nat., 1892 . 
1 Stahl (’94) : Einige Versuche iiber Transpiration und Assimilation. Botanische Zeitung, 1894 . 
6 Rosenberg (’97) : fiber die Transpiration der Halophyten. Ofvers. af K. Vetensk. Akad. 
Forhandl. 
