93 
Physiology of the Genus Cuscuta . 
the vegetative and throughout the reproductive stage to 
divide the larger groups of haustoria, which sometimes bear 
more than one cluster of flowers, without doing any apparent 
damage. This too sometimes takes place in nature. In 
Plate VIII, Fig. i is shown a petiole of Solatium jasminoides , 
Paxt., around which a Cuscuta has twined with many close 
coils. Only under the four clusters of flowers is any part of 
the stem to be seen ; the rest, above, below, and even in this 
close haustoria-bearing spiral, has atrophied and finally dis- 
appeared, leaving but slight traces. Manifestly these little 
clusters, each supplied with food by the very small number 
of haustoria beneath it, have now become individual plants. 
They remind us of the large and apparently isolated flowers 
of Brugmansia and Raffle sia, but we know 1 that the great 
flowers of Brugmansia (and it is the same in Raffle sia) are 
connected with one another by strands of thin-walled meris- 
matic cells running through the cambium of their host. There 
is nothing, however, either on the surface or in the tissues of 
the host, which connects these flower-clusters of Cuscuta ; they 
are absolutely isolated finally, though of course perfectly and 
evidently connected at an earlier stage. It is in part owing 
to its ability to bear, without serious if any injury, division 
Into many small parts, and to its even itself so dividing at 
times, that the Dodder is such a difficult parasite to exter- 
minate when once It has entered a field. 
In most instances the anatomical effects of this parasite on 
its hosts are not marked. It generally robs them so rapidly 
and so completely that they sooner or later succumb without 
having combated its attacks by the formation of any new 
structures, and even without having shown any renewed 
growth as a consequence of the intruder s presence. In the 
petiole figured in Plate VIII, Fig. i, however, we see 
a general enlargement of the whole structure and decided 
1 See Graf zu Solms-Laubach, Die Entwickelung der Bliithe bei Brugmansia 
Zippelii , Botanische Zeitung, 1876 ; also Die Rafflesiaceae, Engler raid Prantl’s 
Die natiirlichen Pflanzenfamilien, Lieferung, ’35, 1889. G. J. Peirce, loc. cit., 
p. 318 et seq. 
