( ( ( ( ( ( His apron ) ( is ( fringed ( with frost ) ) ) ) , ) and ) ( ( ice crystals ) ( cover ( the floor ) ) ) ) . )
(ROOT (S (S (NP (PRP$ His) (NN apron)) (VP (VBZ is) (VP (VBN fringed) (PP (IN with) (NP (NN frost)))))) (, ,) (CC and) (S (NP (NN ice) (NNS crystals)) (VP (VBP cover) (NP (DT the) (NN floor)))) (. .)))
His apron is fringed with frost, and ice crystals cover the floor.
(ROOT (S (NP (NP (DT The) (NN ice) (NNS crystals)) (SBAR (WHNP (WDT that)) (S (VP (VBP form) (PP (IN on) (NP (DT the) (NN ground))))))) (VP (VBP are) (VP (VBN called) (S (ADJP (JJ frost))))) (. .)))