of some Phanerogamic Parasites . 323 
When they branch into the wood or bast of the host, they are 
not in so favourable positions for securing food, they are not 
so well nourished, their cells cease to grow and presently 
become separated from one another. But those branches 
which penetrate into the wood find starch stored in parenchy- 
matous cells, and can therefore survive for a long time ; 
whereas those which grow into the bast have no such stores 
to draw upon, and sooner become inactive and dead, after 
thickening their walls. An extreme case of thickening is 
shown in Fig. II, Plate XIV. 
The chains of cells in the cambiums are probably, therefore, 
extremely reduced roots composed entirely of merismatic 
cells. Professor Strasburger has suggested the name of 
embryonic tissue , since from this, as from the simple tissue 
of the embryo, the new plant is developed. Graf Solms 1 has 
compared these chains to the mycelium of a fungus — ‘ Die 
Vegetationsorgane der Rafflesiaceae sind auf einen glie- 
derungslosen, intramatricalen Thallus reducirt, der haufig vollig 
den Charakter eines Pilzmyceliums annehmen kann ’ — but the 
evidently cellular character of these chains makes the com- 
parison, though suggestive, misleading. It seems to me better 
to call these chains of cells growing in the cambium, morpho- 
logically roots, but so reduced in structure that they are 
nothing more than embryonic tissue. 
In Rafflesia Patina , Bl., as Graf Solms 2 has clearly 
shown, there are similar chains of parenchymatous cells, 
growing in precisely the same positions in the host (see 
P'igs. IX and X, Plate XV), and giving rise to buds which 
eventually develop into flowers. In these buds and flowers 
we find conducting tissues of two sorts, tracheids and sieve- 
tubes, which are directly united with the corresponding tissues 
of the host. 
In these two parasites the provisions for securing and 
conducting to a considerable and, until the seeds are ripe, 
1 Engler and Prantl — Die natiirlichen Pflanzenfamilien, 35 Lieferung, 1889; 
Rafflesiaceae. 
2 loc. cit. p. 275. 
Z 
