Where does “helmgras” come from?

helmgras (Dutch) comes from Dutch helm, from Middle Dutch helm, from Old Dutch helm, from Proto-West Germanic helm, from Proto-Germanic helmaz, from Proto-Germanic halmaz, from Proto-Indo-European ḱolh₂mos, from Proto-Indo-European ḱelh₂- — to pierce, strike; to stick; prick; stab.

Ancestry of “helmgras”, step by step

helmgras traces back through two separate lines of ancestry.

via Dutch helm

StepLanguageWordMeaning
1Dutchhelmhelmet; European beachgrass, Ammophila arenaria
2Middle Dutchhelm
3Old Dutchhelm
4Proto-West Germanichelmhelmet
5Proto-Germanichelmazhelmet
6Proto-Germanichalmazhalm; stem; stalk; straw; hay
7Proto-Indo-Europeanḱolh₂mosstalk
8Proto-Indo-Europeanḱelh₂-to pierce, strike; to stick; prick; stab

via Dutch gras

StepLanguageWordMeaning
1Dutchgrasgrass
2Middle Dutchgrasgrass
3Old Dutchgras
4Proto-West Germanicgrasgrass
5Proto-Germanicgrasągrass
6Proto-Indo-Europeanǵʰreh₁-to become green, grow; to grow; to green, to grow
Every word from Proto-Indo-European ḱelh₂-