Thank you, Anne!
Allow me to broaden the question a little bit, by adding two more stems. Please, what would you call them?
First picture has what in Swedish is called bats. A bats can only be one single knob, and it always sits at the bottom of the stem. There is always a small ... stem (for the lack of a better word) between the bats and the foot.
Second picture has a distinct thickening between the stem and the foot
Third pic shows what in Swe is called a stem with a knapp (literally button). The knapp has an "equator", and is always more or less situated at the middle of the stem. (Spherical knobs and other possibilities are simply calle "fancy" stems, with a descriptio attached)
Fourth pic has a "seamless join".
(and thank you, Frank - I'll be off looking for catalogues shortly...)
