I don’t think historically it was ever meant in the biological sense, more a descriptive one, especially by the old hands, remember the descriptive power of much of the Gaelic used by stalkers past was somewhat limited (Meall Mor, Meall Beg, Glas Coire, Coire creag ruadh, big hill, little hill, green Corrie, red Corrie, etc). Harvestable grain hereabouts is still referred to as ‘berries’ by some, no ill intention is ever intended by it, it’s just the colloquial expressions - a ‘fish’ is a salmon, hen or cock!