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MORPHOLOGY AND DISPERSAL OF ONE‐ AND TWO‐SEEDED DIASPORES OF CRYPTANTHA FLAVA
Author(s) -
Casper Brenda B.,
Grant Bruce W.
Publication year - 1988
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1988.tb13509.x
Subject(s) - diaspore (botany) , biological dispersal , biology , descent (aeronautics) , seed dispersal , seeding , perennial plant , botany , herbaceous plant , ecology , agronomy , population , demography , sociology , engineering , aerospace engineering
The wind‐dispersed diaspore of the herbaceous perennial Cryptantha flava (Boraginaceae) consists of one, or occasionally two, nutlets (seeds) enclosed in a pubescent calyx. Physical characteristics of one‐ and two‐seeded diaspores and their rates of descent in still air were compared. Natural dispersal distances in the field of calyces containing 0, 1, or 2 seeds were also measured. Two‐seeded diaspores are wider at the ovary and have a greater total mass, a greater mass of the ovary, and a higher rate of descent in still air than one‐seeded diaspores. Under field conditions, however, there is no difference in how far calyces containing 0, 1, or 2 seeds disperse. Thus rate of descent is not a good predictor of relative dispersal distances in this species. Much of the dispersal in the field must occur as movement along the surface of the ground, and during such secondary dispersal, the greater width of two‐seeded diaspores may compensate for the potentially opposing effect of their greater mass.