Sentence:  Men , <WSD>trees</WSD> , automobiles , houses , and so on - objects continually confronted in everyday life - had each its characteristic blot appearance and became easily recognizable , at the very beginning of tracing , by an inference as to what each was . 
Meaning of the word marked with <WSD> tags:  a tall perennial woody plant having a main trunk and branches forming a distinct elevated crown; includes both gymnosperms and angiosperms