Poaceae have hollow stems called culms plugged at intervals by solid leaf-bearing nodes. Grass leaves are nearly always alternate and distichous (in one plane), and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem and a blade with entire (i.e., smooth) margins.oaceae have hollow stems called culms plugged at intervals by solid leaf-bearing nodes. Grass leaves are nearly always alternate and distichous (in one plane), and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem and a blade with entire (i.e., smooth) margins.
Air conditioning system components consisting of Condensing Unit, Evaporator Coil, Refrigerant line. How air conditioning works is kind of a mystery to many of us. Furnaces are easy to understand, they heat air and blow it around your home in ductwork.
How air conditioning works. The essential ingredients in an air conditioning system are a fan to blow air around, a cold. surface to cool and dehumidify the air, a warm surface and a source of water vapour. In a. large system there will also be a tangle of tubes to distribute the air and collect it again.