subalternately
/sʌbɔːlˈtəːnɪtli/ /sʌbɒlˈtəːnɪtli/adverb
Chiefly Botany. In a subalternate manner; alternately, but nearly oppositely. Now rare.
Origin
Early 17th century (in an earlier sense). From subalternate + -ly, probably partly after post-classical Latin subalternatim.