Dictionary:

decumbent

  (dĭ-kŭm'bənt)

1. Lying down; reclining.
2. Botany. Lying or growing on the ground but with erect or rising tips: decumbent stems.

[Latin dēcumbēns, dēcumbent-, present participle of dēcumbere, to lie down : dē-, de- + -cumbere, to lie down.]

adjective

Lying down: flat, horizontal, procumbent, prone, prostrate, recumbent. See horizontal/vertical/change of position.

Lying on the ground but with growing tips turned upward.

The adjective has one meaning:

Meaning #1: lying down; in a position of comfort or rest
  Synonyms: accumbent, recumbent, reclining