acropetal
adjective
acrop·e·tal ə-ˈkrä-pə-tᵊl 
a-
: proceeding from the base toward the apex or from below upward
acropetal development of floral buds
acropetally
ə-ˈkrä-pə-tᵊl-ē
adverb a-
Word History
Etymology
borrowed from German, from acro- acro- + -petal (in centripetal, zentripetal centripetal)
First Known Use
1875, in the meaning defined above