pentastichous

from The Century Dictionary.

• In botany, five-ranked: in phyllotaxis, noting that arrangement in which the leaves are disposed upon the stem in five vertical rows or ranks, as in the apple-tree, the cones of the American larch, etc.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Bot.) Having, or arranged in, five vertical ranks, as the leaves of an apple tree or a cherry tree.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective botany Having, or arranged in, five vertical ranks.