MONOCARPY AND PSEUDOMONOCARPY IN THE 
CYCADEOIDS 
G. R. WiELAND 
(Received for publication December 24, 1920) 
Seed plants which fruit once only in the normal lifetime, and then die 
down to make way for the new set, are described as monocarpic. The habit 
is of much interest to students of ecology and succession. 
As ordinarily used, monocarpy is a rather fixed term which requires 
some extension, or even redefinition. In a stricter sense, the field of rye 
is monocarpic; though the usage is far less definite in its common application 
to plants much longer lived than annuals or biennials. There would, 
however, be a double reason for not calling a ''bracken fern" monocarpic; 
since after the fertile frond bears its spores, the root-stock grows on, propa- 
gation being only secondarily dependent on either the sexual or the asexual 
generation. And somewhat similarly, any seed plant which, after the wilt- 
ing down of a fertile stalk of one or more seasons, renews its growth from 
the root, is falsely monocarpic. It is an inadvertence on the part of botan- 
ists to cite the "century plant" as truly monocarpic, or any plant which 
does not fixedly persist by reseeding, or solely so persist. 
There appear to be some basic physiologic distinctions or phases in 
monocarpy. The Agave (or Yucca filamentosa, which regularly sends up 
the new buds, with very little germination of seed) does store the materials 
for the fertile shoot. But in such plants the length of the vegetative phase 
may be variable, or doubtless even local and individual. Besides, wherever 
the basal buds grow forward, there is some analogy to the fertile axis of 
limited growth in trees. 
The production of lowers or fruits usually means the growth of pedun- 
cular tracheidal or other structures old in the history of the plant, supplying 
greatly modified or reduced sporophylls; so that fruit maturity may mean, 
not merely exhaustion of the parent stem, but a heavy scar or injury to 
the stem not easily survived. Thus as a plant is modified from age to age, 
and the gap between fruit and vegetative structures widens, proliferation 
of the fertile axis may become difficult or quite impossible. And such has 
in fact become the condition in the vast majority of seed plants with renewed 
growth from the base of flower or cone. Particularly in the conifers the 
occasional appearance of proliferate cones may be regarded as reminiscent 
of a time when there were some normally proliferate types in the ancestral 
series. 
Contrariwise, the budding power of stems divested of their foliage or 
