42 
REPORT ON BOTANY, MDCCCXLI : 
unwarranted, for Schleiden does not say that which the 
author ascribes to him. According to Schleiden, the cyto- 
blast produces other cells, which come forth when the mother 
cell is absorbed. I also beg to state, that Mr. Quekett 
mistakes Schleiden’s meaning, when he asserts (Annals of 
Natural History, vol. v. p. 66), that vessels are produced 
from a cytoblast in a similar manner as the cells. The 
vessel at first can, with difiiculty, he distinguished from a 
cell, hut it soon lengthens itself, and the cytoblast disappears. 
Mr. Quekett supposes the fibres to be produced from small 
granules in a gelatinous mass, which granules join each other 
according to the different formation of the vessels. There is 
much more in Mohl’s opinion which D. Don’s observations 
favour. Meyen, however, was not the first who reduced the 
dotted, the reticulated, and the spiral vessels to one type. 
I have endeavoured to illustrate the structure of the 
Cycadem in the Icon. Select. Anat. Bot. part ii. (1840), t. 1, 
more with a view to determine their position in the natural 
system, than to investigate the formation of the separate 
cells and vessels. A cauloma, from a withered Encepha- 
lartos^ Friderici Gulielmi III., served for the purpose of 
examination. A longitudinal incision through this cauloma is 
represented in fig. 1, one half of its natural size — a part of 
this incision, in natural size, in fig. 2. A large pith in the 
centre, a thin layer of wood, which forms a perfect circle, and 
a rather thicker bark, will immediately be distinguished. Thus 
far the structure appears to be very similar to the structure 
of the stem of the Dicotyledons. But, on more particularly 
observing the bark and pith, there will occasionally be seen 
curved bundles of wood in both, which, on being magnified at 
82 i. d., are seen as bundles of spiroids both in the bark, 
fig. 3, and in the pith, fig. 6. Such a formation is quite foreign 
to the Dicotyledons, and as the longitudinal incision cuts 
through the woody bundles in various ways, it readily suggests 
the conjecture, that they may, perhaps, form a net in both 
parts. This becomes evident, on observing a longitudinal 
incision of the wood, through the medium of a glass of low 
power, fig. 4, where the net of woody tissue extends itself just 
434 
