Apr., 1921] WIELAND MONOCARPY IN THE CYCADEOIDS 
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the evidence for monocarpic tendencies and pseudo-monocarpy in the 
numberless fruits, from the youngest stages of growth to the mature seed 
cones held securely packed between the leaf bases forming the heavy 
protecting outer ''armor" of the short, robust trunks (note Plate IX). 
It was first observed in studying the petrified stems from the Black 
Hills that a tendency to monocarpy was present. In fact, this was con- 
sidered fairly proven in those instances in which the imbedded young axil- 
lary fruits were found throughout the armor. Thus far five of the species 
of Cycadeoidea are viewed as more or less completely monocarpic : 
1. In the trunk fragment from northwest of the Grapevine Valley, 
Colusa County, California, the axils of the old leaf bases are regularly occu- 
pied by groups of robust bracts, few in number and apparently surrounding 
the ends of slender old peduncles. The trunk may of course have died 
down. (An illustration is given on Plate LXX of U. S. Geological Survey 
Monograph XLVIII; the type is in the U. S. National Museum. It is the 
Cycadeoidea Stantoni. Thin sections are not available.) 
2. The type of Cycadeoidea nigra from Boulder, Colorado, is a trunk 
segment of considerable size from the mid-region of a columnar stem sup- 
posedly a meter high. Again each leaf-base axil is occupied by an old, 
rather slender peduncle bearing few and heavy bracts. Thin sections have 
been cut from the armor, and should be amplified. No basal parts of 
fruits have been observed; but as in the preceding instance the fruiting 
space appears occupied, and a final series is indicated. The flowers may 
have failed of conservation, or the stem may be old. This type is receiving 
further study. It belongs to the Colorado School of Mines, and full cita- 
tations and description may be found in Wieland, American Fossil Cycads, 
volumes I and II (Carnegie Institution of Washington Publication 34). 
3. Cycadeoidea Masseiana, a remarkably fine columnar trunk segment 
greatly resembling the foregoing, from the "scaly clays" of the flanks of 
the Apennines, and reposing in the Capellini Museum, Bologna. Thin 
sections regularly cut young, small fruit axes in the axils of the large, old 
leaf bases of the very heavy armor. Again the thin sections should be much 
amplified. But as even the lesser ones cut by both Capellini and myself 
show the fruits, it is certain these are very numerous, and quite uniformly 
young. A fine model of this specimen is in the Yale collection of study 
materials. (Further reference in American Fossil Cycads.) 
4. Cycadeoidea Fisherae, which may be only some varietal form of the 
Cycadeoidea marylandica, from the Potomac formation of Maryland, exhibits 
a most remarkable series of very young axillary fruits. No sections have 
ever been cut from this specimen, the conservation being hardly equal to 
that of either the Italian or the Black Hills trunks; though it is certain that 
nearly all the way from base to apex there is a fruit of some form in the 
axil of each leaf. It is of course possible that two floral forms are present, 
one staminate, the other ovulate; and it may here be remarked that, with 
