266 
Kny . — On Correlation in the 
Voechting l , c whether there does not exist a relation of 
symmetry between root and bud such that when the develop- 
ment of the one is prevented, that of the other will not take 
place?’ 
Certain facts in horticultural experience, especially the 
culture of dwarf trees in pots 2 , tend to support this view : 
but on the other hand, there are many facts which go to 
prove that the various members of the plant-body do not 
always develop at the same rate. 
When the seed of a normal chlorophyll-containing Phanero- 
gam germinates, the radicle usually escapes first from the 
testa, and attains a certain length before there is any 
external indication of the development of the plumule. In 
some cases the degree to which this early root-development 
takes place is very remarkable. Thus G. Haberlandt 3 states 
that the primary root of the Date-seedling may attain a length 
of as much as a metre before the first foliage-leaf unfolds. 
According to Volkens 4 , a very great disproportion exists 
between the root and the shoot of Desert-plants, both as 
regards their length and the rate of their growth. Again, in 
certain epiphytic Aroids, in Carlndovica Plumieri , and in 
Clnsia rosea , the aerial roots which convey nourishment for 
the plant to a height of ico feet and more above the ground, 
it is clear 5 that the development of the roots has taken place 
at the expense of that of the shoot. The same is still 
more markedly the case in some Orchids (A ngraecum globit- 
losum Q , Aeranthes funalis 7 ), and in some Podostemaceae 8 
1 Voechting, Ueber Organbildung im Pflanzenreiche, I, p. 51, 1878. 
2 Voechting, 1 . c., II, pp. 97-107, 1884. See also Reinke, ‘Die Abhaengigkeit 
der Blattentwickelung von der Bewurzelung,’ Ber. d. deutsch. bot. Gesellsch., II, 
p. 376, 1884. 
3 Eine botanische Tropenreise, p. 287, 1893. 
4 Die Flora der aegyptisch-arabischen Wiiste, pp. 23-26, 1887- 
5 A. F. W. Schimper, ‘ Die epiphytische Vegetation Americas,’ Bot. Mitthei- 
lungen aus den Tropen, II, p. 54, 1888. 
6 Pfitzer, Grundziige einer Vergleichenden Morphologie der Orchideen, cited 
by Goebel, Vergleichende Entwickelungsgeschichte der Pflanzenorgane, p. 126, 
1884. 
7 Schimper, 1 . c., p. 48. 
8 Warming, in Fngler’s Bot. JahrbUcher, IV, pp. 220-2, 1883. 
