902 PROFESSOR W. C. WILLIAMSON AND DR. D. H. SCOTT ON THE 
represent portions of this strobilus. The maximum diameter is about 7°5 millims. 
Most of the specimens are considerably smaller. 
The fructification consists of a rather slender axis, bearing numerous whorls of 
appendages, which are of two kinds, fertile and sterile. The former will be spoken of 
as sporangiophores, the latter as bracts. The sterile and fertile verticils succeed one 
another in regular alternation. Above each whorl of bracts is one of sporangiophores, 
then another of bracts, and so on (see Plate 73, photographs 10 and 11). 
The whorls are equidistant from one another, each fertile whorl being placed exactly 
in the middle of the internode between two verticils of sterile bracts. This character 
at once sharply distinguishes the Calamostachys type of, fruit from the Calamitean 
strobilus described in previous papers,* and from the forms described by Weiss,t under 
the name of Palwostachya, in both of which the sporangiophores arise from the angle 
between the sterile whorl and the internode above. In the large cone already 
mentioned (see photographs 10 and 11) eighteen whorls of bracts were present, with 
the corresponding whorls of sporangiophores between them. The total number in the 
strobilus, when complete, was probably somewhat greater. 
Each sterile whorl consisted of about twelve coherent bracts, forming a horizontal 
disc, at the margin of which the bracts became separate from one another, and bent 
sharply upwards, extending at least as far as the second sterile whorl above (see 
photograph 10). Consequently any transverse section of the strobilus passes through 
at least two alternating series of these overlapping extremities of the bracts. It 
follows that each fertile verticil is enclosed by a ring of free bracts belonging to the 
two sterile whorls below (see Plate 73, photographs 12 and 13; Plate 74, photo- 
graph 14). 
The bracts of successive sterile whorls, as already indicated, alternate with one 
another, so that the free extremities of the bracts of any verticil pass between those 
of the verticil next above. This is easily seen in tranverse sections of the strobilus, 
such as those shown in the photographs just referred to. The fact is also evident 
from the tangential sections, in which the distribution of the vascular bundles in the 
coherent disc affords a useful clue, if the free tips of the bracts cannot be seen (see 
Plate 73, photograph 11). 
The cohesion of the bracts serves to distinguish C. Binneyana from the very similar 
C. Ludwigi, Carr., in which they are free throughout almost their whole extent.§ 
The fertile whorls consist of the sporangiophores, a name which we prefer to 
* Wiriiamson, “On a new form of Calamitean strobilus, &c.,” ‘Mem. Lit. and Phil. Soc. of 
Manchester,’ Series 3, vol. 4, 1870; “ Organization,” Part XIV. 
t ‘Steinkohlen-Calamarien,’ Part I., 1876, Plate 15, and Part II., 1884, Plate 16, fig. 2; Plate 21, 
fig. 4; Plate 22, fig. 15. See also Renavit’s Volkmannia gracilis, ‘Ann. des. Sci. Nat., Bot.’ Sér. 6, 
vol. 3, Plate 2, 1876. 
{ There were thirteen in C. N. 997, from which the Photograph 12, on Plate 73, was taken, 
§ See Weiss, loc. cit., Part 2, ‘Atlas, Plate 22, fig. 8. 
