242 MISS MARIETTA PALLIS ON THE 
ist, findet kein vülliges Verfaulen, sondern nur eine Art von Sapropel- 
bildung statt, so dass ihre Haarwurzeln sich in eine schwarze fette Masse 
verwandeln, während die Rhizome ihre Form beibehalten, aber ein 
verkohltes Aussehen bekommen." 
I did not find the dead rhizomes aggregated towards the lower portion of 
the Plav (see p. 262), nor did I find the rhizomes and rootlets transformed 
into a black slimy mass (see Pls. 14, 15, & 16). Dead rhizomes and 
rootlets—more or less slimy and discoloured—oceur in plenty, but dis- 
tributed throughout the entire Plav-layer as well as in its lower portion. 
The living rhizomes which end in the tallest aerial shoots, in fact, start 
at the very base of the Plav (see Pls. 15 & 16) ; growth must therefore 
be active there. Moreover, dead internodes at the base of the Plav 
are likely to drop off. Thus the base of the Plav is in general healthy in 
appearance, rather than the reverse (see Pls. 15 & 16). 1 have never found 
rhizomes and rootlets which were dead and yet retained their shape: the 
resemblance which the dead bear to the living is that of a collapsed to a 
distended balloon. I have never seen rhizomes carbonized in appearance, 
whether alive or dead. The dark colour of the Plav-layer is due, not 
to the decomposed reed, but to the organie soil (see p. 262) which the Plav 
retains as would a filter (see Pls. 14-17). 
(4) * Die Rhizome des oberen Teiles des Plaur leben weiter und senden 
senkrecht zu ihrer Richtung, also gerade nach oben, neue Schilfhalme aus. 
Es kann hier beobachtet werden, wie durch das Wurzelgewebe, etwa in 
einer Tiefe von 40-50 em. [about 15-20 inches], sich die Schilfhalme 
Raum suchen, um an die Oberfläche durchzudringen,” ete. 
As already remarked, the Plav-layer 18 alive as a whole, and since the 
aerial portions are the continuation of rhizomes, they cannot be said to 
arise at any particular depth: they do so everywhere in the Play, at a 
depth which is determined by their order in the branch-system (see 
р. 267). All rhizomes end, will end, or have ended, in an aerial portion, 
whether they be primary, and therefore extend throughout the whole Plav, 
or branched to the 5th or bth degree, and therefore quite short (see 
рр. 248 & 257, РІ. 11). | 
(5) * Zwischen den die Plaurdecke bildenden Rhizomen und Wurzeln 
dringt oftmals das Wasser durch und. gelangt bis zur Oberfliiche, wo es so 
mehr oder weniger eine künstliche Wasserflüche bildet und dem ganzen das 
Aussehen eines Sumpfes gibt.” 
Dr. Antipa’s explanation of what I will call false swamp appears to me 
directly to contradict the fact that Plav is a floating layer : so Jong as Plav 
remains floating, water cannot find its way between tlie rhizomes and rootlets 
and overspread its surface. Isolated pools can, however, be formed on the 
surface of a Play where it is uneven and dips below the water-level. In these 
pools swamp-plants may grow, thus making small swamps of them, The finest 
