Pollen 



The Microspores which give rise to the male Gameto- 

 phytes in seed plants, cf. Pollination. 



Pollen Analysis 



The identification and determination of abundance of 

 pollen in soil deposits, particularly in peat. cf. Palynology. 



Pollen Profile 



A tabular or graphic expression of the occurrence of vari- 

 ous kinds of pollen in deposits of peat or other materials at 

 different depths. 



Pollen Spectrum 



The expression in percentage of the kinds of pollen in 

 one sample of a Pollen analysis (q. v.). 



Pollen Tube 



The tubular growth, male Gametophyte containing the 

 sperms, produced by a pollen grain when it germinates on 

 the stigma and extends into the style of the pistil of a flower. 



Pollination 



The transportation of pollen by wind, insects, or other 

 agent from an anther to a stigma in flowering plants; usually 

 by wind from a pollen-bearing cone to the Ovw/e-bearing 

 cone in conifers. 



Pollution 



Contamination of a habitat with substances which make 

 it less favorable for organisms. 



Polster 



A plant form resembling a cushion, consisting of closely 

 packed stems, dead leaves, and often roots, e. g., many saxi- 

 frages, mosses. 



Polyandry 



The mating of a single female animal with several males, 

 cf. Monogynous. 



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