1895.] Anatomical and Physiological Researches. 115 
Impatiens grows in moist and shaded places and requires a 
large supply of water for its existence. But the leaves of this 
plant do not get wet by rain, and it, therefore, obtains the 
necessary amount of water exclusively through the roots. In 
contrast to Impatiens is Sanicula Europza from similar situa- 
tions. This is decidedly ombrophilous, and the leaves become 
easily wetted by rain. This fact was also proved by submerg- 
ing leaves of both plants in stagnant water, where those of 
Impatiens decayed in three days, and those of Sanicula only 
after eleven days. , 
The xerophytes are, according to the author’s experience, 
often ombrophobic in a greater or less degree. It would ap- 
pear that those with rather dry leaves do not withstand the 
effects of rain as those with thick succulent leaves, as for 
instance sempervivum and echeveria. The hygrophytes con- 
tain, as already mentioned, representatives with foliage of 
both categories, although the majority are very likely om- 
brophilous, but those with ombrophobic foliage are protected 
not only by the locality (shaded places) but also, and quite 
especially, by the waxy covering of their foliage. 
The aquatics are hydrophilous as are also the underground 
roots, which are constantly exposed to the influence of water. 
Another question arises as to the power of plants to resist 
the injurious effect of an excess of water, by which they might 
become thoroughly soaked. We have here to do with a me- 
chanical and chemical power of resistance. The mechanical 
power may be in the ‘‘bloom” that covers the leaves of many 
plants, and which prevents them from being wetted unless 
€xposed to an excessive rainfall. But those leaves that while 
easily wetted by rain are still able to preserve their vitality 
Must possess a purely chemical power. The author believes 
this to consist in the presence of antiseptic substances. e 
has shown by experiments that ombrophilous shoots of Lysi- 
machia Nummularia, Selaginella spp., begonia, tradescantia, 
etc., are able to keep fresh for a long time in a decayed liq- 
uid. He has, also, observed that the presence of such om- 
brophilous organs delays the decomposition of ombrophobic 
organs, when exposed together to a continuous shower of 
water. It would appear therefore that ombrophobic foliage 
iS protected in a purely mechanical way, while the ombro- 
Philous is protected by the presence of antiseptic substances. 
THEO. HOLM. 
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