persistent

Refusing to give up or let go; persevering obstinately.

Insistently repetitive or continuous.

Existing or remaining in the same state for an indefinitely long time; enduring.

Lasting past maturity without falling off, as the calyx on an eggplant or the scales of a pine cone.

Retained permanently, rather than disappearing in an early stage of development.

Persisting or continuing in spite of opposition, warning, remonstrance, etc.; refusing to cease or give up some action, course, or pursuit; perservering: as, a persistent beggar; persistent attempts to do something.

That endures; enduring.

Specifically— In botany, continuing without withering: opposed to caducous, deciduous, or marcescent: as, a persistent calyx (one remaining after the corolla has withered).

In zoology, perennial; holding to morphological character, or continuing in functional activity; not degenerate, deciduous, or caducous, as a part or an organ: as, persistent types of structure; the persistent horns of cattle or gills of newts.

Repeated; continual.