268 Transactions. — Botany. 



Leaves opposite, rather succulent, in early stage of develop- 

 ment vertical, with concave upper surfaces pressed tightly- 

 together, thus affording great protection to the growing-point 

 of the epicotyl. As development proceeds the laminae open 

 out gradually and become horizontal, while at the same time 

 the petioles increase very considerably in length. 



1st pair of leaves (fig. 4) — in plant 15 mm. tall — oblong- 

 spathulate, glabrous, entire, rounded at apex, of rather 

 glaucous green; laminae 3 mm. x 2-75 mm., tapering into 

 the petiole ; petioles almost equal in length to lamina, 1 mm. 

 in breadth, flat on upper surface, rounded on under-surface, 

 which is more or less deeply stained with purple, sheathing 

 just above their swollen connate purple bases. 



2nd pair of leaves similar in most respects to 1st pair, 

 but paler in colour and stained with purple near base ; 

 laminae almost rotund, petioles two-thirds the length of 

 lamina, and midrib more evident than in 1st pair. 



Stem very juicy, slender, and very elastic, quite glabrous, 

 pale yellowish-green stained with purple ; 1st internode 

 4 mm. long, 2nd internode 2 - 5mm. long. 



The adult form of Stcllaria roughii has sessile, linear, 

 succulent leaves, with an acuminate apex, and of an average 

 size of about 17 mm. x 3 mm. These are indeed very different 

 in shape from the long-stalked leaves of the seedling, with their 

 almost orbicular blades. The adult plant grows in nature on 

 " shingle-slips,"* which are often so unstable that when one 

 moves the stones so as to take up a plant carefully the debris 

 from above fills up the hole almost as fast as it is being made. 

 Of soil strictly speaking there is little or none, and that little, 

 when present, is merely coarse sand with a modicum of 

 particles of clay. At a varying distance below the shingle, 

 depending in large measure on the length of time which must 

 have elapsed since the melting of the winter's snow, is a con- 

 siderable amount of moisture. The seed from the plant, which 

 is most likely a biennial, will fall under the shelter of its leaves. 

 Here the young plants will be protected from excessive sun- 

 shine and wind, and, aided by a rapid root-growth, will soon be 

 able to acquire the all-important water-supply. A transverse 

 section of a seedling leaf shows that it is not ill provided even 

 at an early age to resist excessive transpiration. There is a 

 compact palisade and a rather close spongy parenchyma. On 

 the under-surface the epidermis is 2-layered, the cell contents 

 of the inner layer are often stained red, and on both surfaces 

 is a well -developed cuticle. The petiolate rotund juvenile 

 leaves, and the sessile linear adult leaves, suggest comparison 

 with the often-quoted example originally described by Goebel 



* Cockayne, I.e., pp. 129, 130. 



