This paper describes a method using morphological rules and heuristics, for the automatic extraction of large-coverage lexicons of stems and root word-forms from a raw text corpus. We cast the problem of high-coverage lexicon extraction as one of stemming followed by root word-form selection. We examine the use of POS tagging to improve precision and recall of stemming and thereby the coverage of the lexicon. We present accuracy, precision and recall scores for the system on a Hindi corpus.