The Morphology of Ruppia Maritima. 159 
During their growth the young plants showed very clearly the 
manner in which the horizontal rootstock is developed. At first 
the seedling is erect, but soon, as it increases in length, reclines 


Figure 32.—Young seedling, show- Figure 33.— Young seedling, older 
ing development of horizontal root- than preceding one, showing more 
stock. J/r, /2, 23, &c., successively advanced development of horizontal 
older leaves; rz, 72, 73, &c., suc- rootstock. Abbreviations as in pre- 
cessively older adventitious roots. vious figure. 4 natural size. 
5 natural size 
somewhat, and at the same time an adventitious root (Text-fig. 32, 71) 
appears at the first node and grows downward, fixing itself in the 
soil or sand. This is repeated at successive nodes, the shoot re- 
clining more and more, and Text-fig. 32 shows an advanced stage 
where five adventitious roots have been developed, and a sixth (7%) 
is just appearing. Three days after the drawing was made, this 
sixth root had reached the surface of the sand. In this figure the 
roots have almost the appearance of drawing down the stem to a 
horizontal position. Whether or not this is actually the case, a 
horizontal location is ultimately attained, as in Text-fig. 33. Here, 
indeed, the first roots have apparently drawn the oldest part of the 
seedling well down into the sand. 
From this time on the seedling assumes the habit of the mature 
plant. From the nodes upright shoots may arise, which may also 
develop later in the same way into root stocks, thus forming a 
branched rootstock; or it is conceivable that these upright shoots 
may continue in an erect position, ultimately reaching the surface 
of the water and flowering. 
