Hurricane 



(1) A tropical cyclone, especially one in the West Indian 

 region; with winds of hurricane force which blow around 

 the central calm area or "eye" which is very low in atmo- 

 spheric pressure. (2) The highest wind velocity on the 

 Beaufort scale (q. v.), a wind greater than about 75 miles per 

 hour. 



Hybrid 



(1) Genetic; an organism resulting from a cross between 

 parents with different Genotypes (q. v.). (2) Taxonomic; a 

 cross between parents of different Taxa (q. v.). 



Hybridization 



The crossing or breeding of unlike individuals to produce 

 hybrids. 



Hybrid Segregate 



A form produced in the second or later generation after 

 hybridization. 



Hybrid Swarm 



A population of organisms derived through hybridiza- 

 tion, comprising various generations of hybrids and back- 

 crosses; often varying greatly, cf. Back-crossing. 



Hybrid Vigor 



See Heterosis. 



Hydathode 



A pore or gland, usually in leaves, that exudes water. 

 cf. Guttation. 



Hydrarch 



Refers to a Succession or Sere which begins in wet habi- 

 tats such as a pond. cf. Hydrosere, Xerarch. 



Hydraulic Equilibrium 



The condition of absence of flow rate of water in soil, 



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