{ 466 J 
LXXVI. Researches into the Anatomy of Plants. By 
fH. FP. Linx, of Breslau, formerly of Rostock. 
(Concluded from p. 392.] 
3. Tue tracheze are wanting in several plants. T have not 
found them in the genera Lemna, Zostera, Chara, Naias, 
Ceratophyllum of the family of the Naiades. We might se- 
parate these genera from the other plants of this family which 
are furnished with them. Ihave found them, although small, 
in the genera Hippuris, Myriophyllum, Potamogeton, Rup- 
pia, Zanichellia, Callitriche. I have not had an opportu- 
nity of examining the species of the genera Sawrurus and 
Aponogeton in this respect. The trachez are wanting in 
all the mosses, in the lichens, the algz, and the mushrooms. 
It is not possible that so many plants can be deprived of 
the vessels which contain the nourishing sap. There are 
besides, many large trees which grow very fast, such are the 
firs, the cypress, and the juniper, the tracheze of which are 
so small that several authors have denied their existence in 
all these trees. I have seen some, however, particularly in 
the young shoots, but so small thatthey were hardly percep- 
uble with the best microscopes. It seems to me httle pro- 
bable that trees of such a size have their nutritive vessels so 
small, while plants much smaller contain some of a consi- 
derable diameter. The fibrous vessels, on the contrary, are® 
found in almost all plants, and are only wanting in some 
lichens, some algz, and some champignons, in general in 
very small plants, and perhaps they exist in these vegetables, 
but so minute that the observer cannot discover them. In 
the mosses they are very distinct: in almost all the lichens 
we see twisted fibres, forming a kind of tuft or bur in the 
middle of the plant: in the ruc? the fibres are twisted in the 
same manner, but they are of a gelatinous substance: in 
most mushrooms we see them very distinctly. It was only 
in the crustaceous Lichens, the Conferyze of Linneus, and 
the smallest sized Champignons, that I could not findthem. 
4. Itis not to be presumed that the sap can move through 
the cellular texture; the partitions would prevent this mo- 
tion, which must be very rapid. Supposing that there are 
pores, as M. Mirbel thinks, these pores must be much 
smaller than the orifices of the fibres, and the flowing of the 
sap by these pores must take place very slowly. Finally, if 
we peel off the bark of a tree, the pith of which is dry, it 
will still vegetate a long time, although there remains but 
very 
