Layering 



The appearance of plants or plant parts, or their remains, 

 in horizontal divisions, syn. Stratification. 



Leaching 



The removal by percolating water of soluble constituents 

 from the soil or other material. 



Leafmold 



The lower layer of the A horizon, lying on the mineral 

 soil, consisting mostly of well-decomposed, finely-divided 

 organic material. 



Leaf-size Classes 



The arbitrary groups of leaves based on the area of 

 blades, as proposed by Raunkiaer, in square mm: Leptophyll 

 25, Nanophyll 225, Microphyll 2025, Mesophyll 18,225, 

 Macrophyll 164,025, Megaphyll larger than 164,025. 



Legume 



(1) A plant belonging to the family Leguminosae, e.g., 

 pea, alfalfa. (2) The fruit of Leguminosae. 



Leguminous 



Refers to the pea family, Leguminosae. 



Lemming 



One of the small rodents in genus Lemmus or Die- 

 rostonyx, order Rodentia, of circumpolar distribution. 



Length-of-day 



See Photoperiodism. 



Lentic 



Refers to the standing-water series; lakes, ponds, swamps. 

 cf. Lotic. 



Lenticel 



A pore on the surface of woody stems or roots, filled 

 with loosely arranged cells that permit diffusion of gases 

 between the atmosphere and the interior of the plant. 



203 



