Defendants first assign error to the denial of their motion for a directed verdict. They contend that their motion should have been allowed, first, because plaintiff’s evidence showed that she held only a life estate in the property, the remainder interest being in her two sons who are not parties to this action. There is no merit to this contention. As life tenant plaintiff was entitled to the immediate possession of the property, and she was entitled to recover at least nominal damages for any trespass which interfered with her possessory interest. Lee v. Lee, 180 N.C. 86, 104 S.E. 76 (1920). It has long been recognized that one in possession of real property holding rights far less substantial than those of a life tenant may maintain an action against a third party trespasser to recover for injury to his possession. See, e.g., Smith v. Fortiscue, 48 N.C. 65 (1855); Annot., 12 A.L.R. 2d 1192 (1950); Dobbs, Trespass to Land in North Carolina — Part I. The Substantive Law, 47 N.C. L.Rev. 31, 40-42 (1968). In such a case, of course, the owner of the title is a proper and may be a necessary party to an action of trespass, when the wrongful invasion of the property involves an injury both to the possession and to the inheritance. Tripp v. Little, 186 N.C. 215, 119 S.E. 225 (1923). However, the failure to join even a necessary party is not grounds for dismissal of the action, the remedy being to add the necessary party, which may be done “by order of the court on motion of any party or on its own initiative at any stage of the action.” G.S. 1A-1, Rule 21. In the present case, the plaintiff, as holder of the life estate, had a right to maintain this action to protect her interest in the property. Nonjoinder of the remaindermen did not entitle defendants to a directed verdict, but at most entitled them to have the re-maindermen joined as parties upon their motion to do so. Defendants made no such motion.

*381Defendants next contend that their motion for directed verdict should have been allowed because plaintiff failed to prove her title in any of the ways enumerated in Mobley v. Griffin, 104 N.C. 112, 10 S.E. 142 (1889). We do not agree. The 1926 deed to plaintiffs father constituted color of title, and plaintiff connected herself with that title by introducing the wills of her father and mother. She also testified that her father had farmed the property during his lifetime, and that after her father’s death in 1943, her mother and the plaintiff had continuously sharecropped the property up to the time of the trial in 1976. Thus, plaintiff’s evidence, when viewed in the light most favorable to her as it must be in passing on defendants’ motion for directed verdict, was sufficient to show open, notorious, continuous, adverse, and unequivocal possession of the land in controversy, under color of title in herself and those under whom she claims, for more than twenty-one years before the action was brought. This was one of the methods listed in Mobley v. Griffin, supra, by which a prima facie showing of title may be made.

Finally, defendants contend their motions for a directed verdict should have been allowed because plaintiff’s evidence was insufficient to establish the location on the ground of the boundary lines of the property described in the complaint. Again, we do not agree. The plaintiff’s witness, J. C. Shearin, a registered land surveyor and civil engineer who was accepted by the court as an expert surveyor, testified to the several surveys which he had made of the property, to the location on the ground of the lines which he had established by those surveys, to the old marked corners which he had found, and in particular to the exact location of the western boundary line across which defendants had commenced construction of their building. He also testified to the identity of that western boundary line with the western line of the tract described in the 1926 deed to plaintiff’s father. This evidence sufficiently located the boundary lines of plaintiff’s property to withstand defendants’ motion for a directed verdict. We find no error in the denial of defendants’ motion.

Defendants’ second assignment of error is that the court erred in allowing plaintiff’s motion for a directed verdict. This assignment of error has merit. Plaintiff had the burden of proving that she had title to the property and that defendants had trespassed thereon. Essential for that purpose was the testimony *382of the plaintiff and of her witness, J. C. Shearin. A directed verdict may not be granted in favor of the party having the burden of proof when his right to recover depends upon the credibility of his witnesses. Cutts v. Casey, 278 N.C. 390, 180 S.E. 2d 297 (1971). In the present case plaintiff’s right to recover depended upon the credibility of her witnesses, and it was error to direct a verdict in her favor. For this error there must be a

New trial.