A'a contains clinkers and is brittle.
Pahoehoe is ropey, like chocolate syrup poured over ice cream.
Pahoehoe lava presents a surface difficult for plants to colonize. It has few cracks to provide for soil and moisture. A'a is more quickly colonized and covered with plant growth. A'a and pahoehoe are two words from the Hawaiian language that will be found in most large English dictionaries. The photo below shows both types of lava.