Apr., 1921] WIELAND MONOCARPY IN THE CYCADEOIDS 
223 
and certainly a few of the topmost of the cones below the terminal bud 
appear greener and less mature. In one cone inserted 6 centimeters below 
the apex, the seed stem mass is split off from the receptacular cushion, with 
the lower portions of the stem bundles left behind adherent to the cushion, 
so that these bundles are seen to traverse the clear silica the full distance 
between the cushion and the seed stem mass. The seeds of this cone are 
not conserved, but the bundles show a somewhat similar tension or tearing 
out in occasional cones farther down in the series. In a smallish cone five 
centimeters below the terminal bud, the basal seed stem mass is again all 
that is conserved, but it appears mature. These two bases of cones may be 
seen in the photograph of the full longitudinal section of the entire trunk 
segment (Plate 43 of American Fossil Cycads, volume II). 
PSEUDOMONOCARPOUS TyPES 
Apparently monocarpy is a phenomenon at present confined to the 
angiosperms. At least no characteristic instances now occur in the gneta- 
leans, and none in the conifers. The latter are no longer capable of annual 
or biennial fructification, as perchance in some remote period of their 
history. The dwarf or pygmic species are simply those of the high moun- 
tains, such being stubbornly coniferous and longevous. 
It is therefore curious to find that there is in the cycadeoids a near 
approach and parallel to a kind of pseudomonocarpy found in several 
conifers of the CaHfornia Sierras. The so-called ''knob cone pine" (Pinus 
atienuata) occurs in much restricted "close willowy groves" of the dry slopes 
— in the San Bernardino range at about 3,000 feet, or along lower forest 
limits. It is lower and more abundant in the Shasta region. This pine 
varies greatly in size, from 30 meters high down to only two, though mature. 
(The wood is of low specific gravity, only 0.35.) At the age of seven or 
eight years the large cones begin to appear, borne close to the stem or larger 
branches, and there persist from year to year until the older series is quite 
imbedded in the bark. So indurated and resistant are the sporophylls in 
fact that often the seeds are not shed until the trees die, the groves being 
periodically fire swept. Then, the cones split open and reseed as if from a 
single crop, the trees in the " stands "always being of the same age.^ A life- 
like picture of this singular pine is given by John Muir. 
Also, Pinus CouUeri, as I noted in the San Bernardino range, bea-rs while 
younger a certain resemblance to the **knob cone." The very large cones 
are then borne only on the excurrent stems, and the first cones may abort 
for some distance up the trunk, leaving near the summit only a few, or but 
^ It is evident that the cones near the base of an old tree reached maturity while the 
stem diameter was yet small, and that if they remained in the position where they first 
grew, they must become imbedded in the solid stem wood. But what happens is 
that the quite sessile cone is torn from its seat and carried outward by stem growth, with 
the bases deep set in the bark. The long persistence of the cones is partly due to an un- 
commonly hard resinous lacquer-like coating. 
