A Fourth Contribution to our Knowledge of the Anatomy 
of the Cone and Fertile Stem of Equisetum. 
BY 
ISABEL M. P. BROWNE. 
With Plate XXI and twelve Figures in the Text. 
I. Material. 
I N the course of the present investigations the cones of three species, 
E. sylvaticum , L., E. debile , Roxb., and E. variegatum, Schleich, were 
studied. Of E. sylvaticum three cones, A, B, and C, were cut serially into 
transverse sections. In the cases of Cones A and B, the sections extended 
to a level just below the annulus, but in Cone C the series ended just below 
the insertion of the lowest whorl of sporangiophores. A fourth cone, D, was 
cut serially into longitudinal sections. 
Five cones of E. debile , henceforward referred to as Cones A, B, C, D, and 
E, were cut serially into transverse sections, and a sixth cone, F, was cut into 
serial longitudinal sections. Below Cones A, B, and C the series of sections 
was continued so as to include the uppermost node of the cone-bearing 
branch, while below Cone E the series of sections extended to a point just 
below the second node in a downward direction. 
Of E. variegatum serial transverse sections were obtained of three 
cones, A, B, and C. Below Cone A the series of sections was prolonged, so as 
to include two vegetative nodes. Of a fourth cone, D, serial transverse 
sections were made of the region transitional from annulus to cone. 
The following table gives particulars as to the size and constitution of 
the cones. 
In all 
cases, 
except in that 
of Cone 
C of E. sylvaticum , the 
Species. 
No. of 
whorls. 
No. of spor- * 
angiophores. 
Height of stele. 
Greatest width of stele. 
E. sylvaticum . 
A. 
13 
162 
circa 
18.8 
mm. 
circa 
!*5 
mm. 
55 55 
B. 
1 1 
1 1 6 
55 
18.7 
33 
55 
1 *3 
5? 
55 55 
C. 
14 
149 
55 
17 
33 
55 
1.28 
55 
E. debile . 
A. 
9 
68 
55 
10.5 
33 
55 
i -5 
55 
33 33 
B. 
9 
60 
,, 
5 
33 
55 
0.46 
55 
i> ?> 
C. 
6 
35 
55 
8.2 
„ 
55 
o-6 
5J 
3J 33 
D. 
6 
32 
55 
7 . 2 : 
) 33 
55 
i*4 
5 5. 
33 >3 
E. 
7 
38 
55 
9 
33 
5? 
Q, 75 
55 
E. variegatum. 
A. 
5 
35 
5) 
2, 5 
>3 
5? 
o-6 
55 
55 5 5 
B. 
4 
2 5 
55 
2.4 
„ 
55 
o-5 
5? 
5 5 5 5 
C. 
4 
2 5 
5 > 
2.4 
33 
55 
o-45 
55 
[Annals of Botany, Vol. XXXV. No. CXXXIX. July, 1921.] 
