hypogeal
/ˌhaɪpəʊˈdʒiːəl/; /ˌhɪpoʊˈdʒiːəl/Definitions
1. adjective
relating to or developing from a seed that germinates and grows without exposure to air, especially a type of seed that germinates underground
“The plant is hypogeal and grows underground until it reaches the surface.”
2. noun
a seed that germinates and grows underground
“The farmer planted hypogeal seeds in the field.”