Mlcrospore 



The smaller of two kinds of spores produced by plants 

 such as Selaginella and the Spermatophytes, e. g., pollen 

 grains. 



Microstand 



A group of plants that occupies a Microhabitat (q. v.). 

 cf. Stand. 



Microtherm 



An organism that can develop in cool and short sum- 

 mers, e. g., barley, spruce trees, cf. Megatherm, Mesotherm, 

 Hekistotherm. 



Microtome 



An instrument for cutting very thin sections of tissue 

 for microscopic study. 



Mictium 



A heterogeneous mixture of species such as occurs often 

 in a transition zone between two kinds of stands. 



Midgrass 



A grass two to four feet tall, in contrast to a tallgrass 

 which is five feet or more tall, e. g., Koeleria cristata. cf. 

 Medium-height grass, Shortgrass, Highgrass. 



Migrant 



An organism that is undergoing Migration (q. v.). 



Migration 



(1) The movement of a plant or one or more of its parts, 

 such as fruits, from one area to another. (2) The movement 

 of an animal beyond its regularly occupied geographic loca- 

 tion or Home range (q. v.). cf. Emigration, Immigration, In- 

 vasion. 



Migrule 



See Diaspore. 



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