Embryo of Sequoia sempervirens. 3 
In the development of the endosperm in Sequoia , Arnoldi sees a striking 
similarity to that which occurs in Gnetuni. 
In the same year (1900) Arnoldi published some observations on the 
archegonia and pollen-tubes in Sequoia sempervirens . He finds that the 
archegonia arise from peripheral endosperm-cells and are present in large 
numbers and may appear singly or in groups. Each archegonium has 
two neck-cells but none contain a ventral canal cell. The position taken 
by the pollen-tubes is between the nucellus and the endosperm and they 
eventually lie opposite the archegonia. 
In his more recent work, Arnoldi (1901) touches upon fertilization and 
the development of the embryo. In addition to Sequoia this short paper 
also discusses these phases in the life-history of Taxodium , Cryptomeria , 
Cunninghamia y Glyptostrobus, and Sciadopitys . In Sequoia sempervirens , 
which concerns us more particularly, he finds that the pollen-tube eventually 
contains two male cells and two free nuclei, of which one is the tube 
nucleus. At the time of fertilization the male cell becomes elongated 
or even spirally twisted. The male and female nuclei fuse in the middle 
of the egg and then move to the base of the archegonium, where the first 
segmentation-spindle is developed. Following this division two cells are 
organized, one behind the other. The lower of these divides again so 
that the embryo now consists of a row of three cells. The lower cell of 
the first division functions no further and soon becomes disorganized. 
On the sporophyte of Sequoia , Peirce (1901) has contributed some 
interesting and important observations on fasciation, albinism and vegeta- 
tive reproduction. 
Methods. 
There are few groups of plants that offer more difficulties in the way 
of cytological research than the Coniferales. The structures that are of 
greatest cytological interest are usually buried deep in the other tissues, 
thus requiring very careful dissection before being placed in the killing 
fluids. Then, again, if resin is present, as is usually the case, a rapid 
penetration of the fluid is impossible. 
These and many other difficulties probably account for the frag- 
mentary nature of the work that has been done. A brief statement of 
the methods adopted in the following work on Sequoia may be useful to 
others working in this field. The fixing fluids experimented with were 
as follows : — ■ 
1. Flemming’s weak solution — 
25 c.c. of 1 °/ o chromic acid 
10 c.c. of 1 °/ o acetic acid 
10 c.c. of 1 °/ o osmic acid 
55 c.c. distilled water. 
