As "Pterostylis sp." could be any Pterostylis, it is probably fair to leave it as rare or uncommon. A record of Pterostylis sp. could be of an unidentified P. nutans, common, or it could be of P. oreophila which is critically endangered and rarely seen nationally. We could make further categories within "Pterostylis sp.", but that would make things more complicated with data. It is easier to keep things simple and keep it to one category and treat all instances of an unidentified Pterostylis as potentially being a rare entity.