What kind of dark wood with a wavy grain is found in Poland?

Question

We just bought an antique table and chairs that was made in Poland about 1900-1910. It is a naturally dark wood, with a grain somewhat like oak, but not as wild. The table leaves were still in the original wood boxes they were brought over in. I just lemon oiled them, and they darkened right up. The style of the table is a heavy plank top round with a big pedestal and four slightly wavy legs. The chairs are very much like a combination of Shaker and Mission. Pretty simple, with legs that were handmade, each one is slightly different.

Answer 1

sounds like walnut or oak. both are widely used for quality furniture. The oak darkens with age and can get almost black in colour- rather typical of Gdansk (Danzig) furniture (very dark, very heavy style)
Of course there were thousands of manufacturing sites in Poland, so try looking for more clues