The two Defendants claim title ownership of the four lots of land in issue by virtue of deeds to their predecessors in title from the Town of Poland which the Defendants contend acquired title through the foreclosure of liens placed on the property for unpaid taxes assessed in the years 1961, 1962 and 1964. The Plaintiff, who has the record title to three of the lots of land except for the effect of these tax liens, brings these two real actions to recover the property. The Plaintiff’s only title to the fourth lot, the Philip Winslow lot, had been acquired by virtue of a quitclaim deed, dated April 28, 1964, from the Town of Poland, similar to those given by the Town to the Defendants’ predecessors in title to the four lots. The facts in the two cases are essentially parallel and the legal issues are identical. The Justice in the Superior Court gave the Plaintiff judgment for possession of the land in *547question and the matter comes before us on the Defendants’ consolidated appeals.1
We find that the issue of validity of the appointment of the Town Manager as Tax Collector for the years 1961, 1962 and 1964 proves determinative of both appeals.
After hearing on the two consolidated cases the Single Justice found that:
“7. The Town Manager of Poland, who served in that capacity during all of the years in question, was first appointed March 30, 1959, and his one-year contract of that date provided he should exercise the duties of Town Treasurer and Tax Collector.
8. The procedure for annual reappointment of the Poland Town Manager, in 1960 and in all subsequent years through 1966, kept in each instance to the following pattern: After the close of a formal Selectmen’s Meeting, and in the absence of the Town Manager, the Selectmen informally discussed renewal of his contract. Thereafter at a formal Selectmen’s meeting there was a motion and vote to reappoint the manager, making no mention of the offices of Treasurer or Tax Collector; and a new or renewal contract was prepared and signed by the Selectmen and the Manager, again making no--mention of the offices of Treasurer or Tax Collector.
9. The evidence clearly establishes that the Selectmen, Manager and townspeople all considered the Manager to be the Town Treasurer and Tax Collector, and that he acted in both of said capacities de facto; but the evidence also establishes that he did not hold either office de jure.”
As we have frequently held, title acquired by virtue of a tax lien is a nullity unless all conditions precedent to its foreclosure have been complied with. The law protects the delinquent taxpayer from forfeiture of his property except under strict construction of statutory requirements. Arsenault v. Inhabitants of the Town of Roxbury, Me., 275 A.2d 598 (1971).
The Defendants, relying upon the foreclosure of the tax lien mortgages and the expiration of the periods of redemption, have the benefit of the statutory principle that the tax lien mortgage is
“ . . . prima facie evidence in all courts in all proceedings by and against the municipality, its successors and assigns, of the truth of the statements therein and after the period of redemption has expired, of the title of the municipality to the real estate therein described, and of the regularity and validity of all proceedings with reference to the acquisition of title by such tax lien mortgage and the foreclosure thereof.” 2
At this point, we should note that the Selectmen’s appointment of the Manager as Treasurer had no validity. During the entire period in question the provisions of R.S.1954, Chap. 91, § 15 and later of 30 M.R.S.A. § 2055 required that the Treasurer be elected by ballot at the annual town meeting and this office was not at that time one which the Selectmen could fill by appointment.3
Although it is clear that the Manager was not legally appointed to serve as Treasurer we see little value in discussing the issue of whether a Treasurer’s duties are such as to affect the validity of tax liens as we consider that the qualifications of *548the Tax Collector are critical as to this issue. The Tax Collector is the sole officer authorized by the statute to sign and record in the Registry of Deeds the tax lien certificate, to file the copies of the certificates in the Treasurer’s office, and to send notices to the record holders of mortgages.
It was held by this Court in Payson v. Hall, 30 Me. 319 (1849), and reiterated in Baker v. Webber, 102 Me. 414, 67 A. 144 (1907), that the effectiveness of a tax deed executed by a Tax Collector depended upon proof that the Collector has been legally elected to the office.
“The party is required to produce the collector’s deed not the deed of a person assuming without right to act in that capacity.” Payson v. Hall, supra, 30 Me. at 326. (Emphasis added.)
While these cases dealt with earlier methods of enforcing tax collection there can be little doubt that equally persuasive reasons for proof of qualifications of the Tax Collector are present when the ownership in issue is dependent upon a title obtained under automatic foreclosure of tax lien mortgages which no one but a Tax Collector de jure may execute. A valid appointment of a Tax Collector is crucial to the viability of his tax liens.
The Plaintiff, in light of the statutory declaration of prima facie proof of regularity, has the burden of demonstrating that the appointment of the Manager as Tax Collector did not comply with legal requirements, as she has raised this issue.
The authority for appointment of a Town Manager to other town offices at the times concerned with the 1961 and 1962 taxes is found in P.L. 1957, Chap. 405, § 41 which became R.S.1954, Chap. 90-A, § 41, and reads:
“Sec. 41. Town manager form of government. A town may adopt the town manager form of government at a meeting held at least 60 days before the annual meeting.
T. At the time of adoption, the town may determine which offices the manager is to hold, or may delegate that power to the selectmen.
A. A manager may not be a moderator, selectman, assessor or member of the school committee.
B. When a town had determined the offices which its manager is to hold, the selectmen shall appoint him annually to each of those offices.” (Emphasis added.)
In 1961 and 1962 it was voted at the annual town meeting that the Manager should hold the offices of Treasurer and Tax Collector and it thus became the duty of the Selectmen, when engaging a Manager, to appoint him to these offices also. In 1963 this statute was amended to state that the Selectmen, independently of the town meeting, shall determine what other offices the Manager shall hold.
The Defendants attack the Justice’s conclusion that the Town Manager did not hold these offices de jure. They point out that when in 1959 the town adopted the Town Manager form of government this Town Manager’s original written contract stipulated that the Manager should exercise the duties of Town Treasurer and Tax Collector. They argue that each annual decision by the Selectmen to continue the same Manager’s employment as Manager constituted an appointment to those other offices also.
Although the testimony — and, at least one of the minutes — speak of a successive Manager’s contract as a “renewal”, none of these annual renewals of the Manager’s contracts mention the office of Tax Collector and the original minutes of the Selectmen’s meetings are silent as to any appointments of Tax Collector after 1959.
The testimony shows that the Selectmen’s annual agreements with the Manager that he should also hold the office of Tax Collector were arrived at very informally. Witnesses testified that there was “a *549lengthy discussion” about it, that the Selectmen so “mutually agreed”, and that “it was the understanding”. The Town Manager testified “it was my understanding that when this [1961] contract was signed it was a renewal [of the original contract]”.
The testimony of the witnesses as to this is exemplified by this passage during direct examination of Mr. Fernald, a Selectman:
“A It had been the generally accepted practice that while the Selectmen were discussing the town manager’s contract the town manager was absent, because we felt that it was better when he wasn’t there, and his duties were discussed and the 1960 contract was renewed, the 1959 contract.
We discussed the different duties he was to perform. We discussed his ability as to each, and came to the agreement, and this was at a Selectmen’s meeting when, at that time, no minutes of those meetings were kept. They were special meetings. And the town manager was advised the following day that we had signed his contract.
Q Was it specifically determined that the town manager was to serve as tax collector, treasurer, road commissioner, overseer of the poor in 1960 ?
A In discussing the contract, yes. We renewed his contract on the previous year’s contract to perform those duties.
Q And you were one of the signers of the 1960 contract ?
A Yes, sir.
Q When it was signed it was specifically understood, although not contained in the contract, that he was to serve as tax collector, treasurer, road commissioner and overseer of the poor ?
A That is right, sir.”
More than six years later, on July 29, 1969, the Secretary of the Board of Selectmen purported to amend the minutes by adding:
“I, R. A. Waterhouse, Jr., under oath, hereby amend the record of the Selectmen’s Meeting of the Town of Poland held March 19, 1963 by adding the following omission therefrom:
‘Voted, that Raymond F. Parsons is appointed tax collector, treasurer, road commissioner and overseer of the poor for the Town of Poland for the year April 1, 1963 to March 31, 1964.’ ”
A similar amendment was added at the same time for each year now in issue.
We are of the opinion that these late amendments — however well intended— cannot destroy the intervening rights of owners of affected properties. Moreover, they do not purport to show that the appointments of the Collector during the years in question were made in writing — a statutory requirement which none of the rest of the evidence has been able to supply.
P.L.1957, Chap. 405, § 36 subd. II is explicit in its demands for formality of appointment of town officials:
“The appointment of any town official or deputy shall be in writing and shall be signed by the appointing party.”
In construing a statute as being mandatory or directory the purposes of the statute as well as the language must be considered. It has been considered by most jurisdictions that the word “shall” should be construed as imperative and mandatory and not merely directory and permissive. Barnes v. State ex rel. Pinkney, 236 Md. 564, 204 A.2d 787 (1964); North Hampton Racing & Breeding Ass’n., Inc. v. Conway, 94 N.H. 156, 48 A.2d 472 (1946); Harvey v. Board of Chosen Freeholders of Essex County, 30 N.J. 381, 153 A.2d 10 (1959); 50 Am.Jur., Statutes, § 28; 82C.J.S. Statutes § 380.
In our opinion the language of this statute lends itself to a logical mandatory in*550terpretation. The Legislature recognized the necessity of having permanent records each year as to who was holding the various town offices. Persons dealing with town officials needed to know with assurance the identity of the person authorized to act. The Legislature, aware of the frailties of human memory and the possibilities of misinterpretation of official actions taken orally and informally, determined that the purpose of certainty could best be met by requiring written appointments to town offices. We conclude that the language “shall be in writing” is a “matter of substance” and not a “matter of convenience” and that the consequences that result from construing the language as mandatory are reasonably anticipated to promote the purposes of the statute. International Brotherhood of Teamsters, Chauffeurs, Warehousemen and Helpers of America, Local 145 v. Shapiro et al., 138 Conn. 57, 82 A.2d 345 (1951).
We have concluded that the tax lien mortgages in question were invalid unless the Tax Collector held the office de jure during 1961, 1962 or 1964 and that he did not hold the office unless his appointment was in writing. The statute has made the filing of the tax lien mortgage prima facie proof of the regularity of all prior proceedings necessary to its validity including, of course, the proper appointment of the Tax Collector. Inhabitants of Town of Lincolnville v. Perry, 150 Me. 113, 104 A.2d 884 (1954).
“. . . [P]rima facie evidence in legal intendendment means evidence which if unrebutted or unexplained is sufficient to maintain the proposition, and warrant the conclusion to support which it [has been] introduced . . .” Carroll v. Boston Elevated Railway Co., 200 Mass. 527, 86 N.E. 793, 797 (1909).
While no witness testified specifically that there were no written appointments of the Tax Collector, no written appointments were offered and the witnesses described at length the manner in which the Selectmen had informally and verbally decided that the Manager should serve as Tax Collector and that the Manager “was advised the next day that we had signed his contract [i. e. his contract as Manager]”. From the abundance of testimony as to the manner in which the appointment was made, an inference could be drawn that there was no appointment in writing, thus overcoming the statutory prima facie proof of regularity.
While the Single Justice made no specific finding that the appointments of the Tax Collector were not in writing, he found that the procedures followed by the Selectmen fell short of constituting valid appointments to that office. This finding was not clearly erroneous.
There was no error in the Justice’s conclusion that the Plaintiff was entitled to judgment for possession of the land described in her complaint against the Defendant Ralph L. Poland, Sr. which is Docket No. 4119 or in his finding that the Plaintiff was entitled to judgment for possession of the first parcel of land described in her complaint against the Defendant Robert D. Merrill which is Docket No. 4118.
A different situation prevails, however, in the Plaintiff’s claim against Mr. Merrill for possession of the so-called Philip Winslow lot, the second parcel described in the complaint which is Docket No. 4118.
In order to be entitled to judgment for possession of this parcel the Plaintiff must prove the title she has alleged. Dolloff v. Gardiner, 148 Me. 176, 91 A.2d 320 (1952); Wyman v. Porter, 108 Me. 110, 79 A. 371 (1911); Day v. Philbrook, 89 Me. 462, 36 A. 991 (1897).
The Plaintiff must show a better title than the Defendant’s. Coffin v. Freeman, 82 Me. 577, 20 A. 238 (1890). If the Plaintiff shows no title she cannot prevail even though she proves the Defendant has no title. Wyman v. Porter, supra; Derby *551v. Jones, 27 Me. 357 (1847). Although we have said that possession under color of title is better than no title, Wyman v. Porter, supra; Stetson v. Grant, 102 Me. 222, 66 A. 480 (1906), here the Plaintiff has shown no possession under color of her only claimed source of title — the 1964 deed from the town.
It follows that the invalidity of the appointment of the Tax Collector in 1961 rendered the town’s tax lien for the 1960 taxes on the Philip Winslow lot ineffective and therefore the town acquired no title to the Philip Winslow lot by virtue of this lien. In short, the record here does not demonstrate any title to this lot in either Plaintiff or Defendant.
The Plaintiff’s appeals are dismissed.
The Defendant Ralph L. Poland’s appeal is denied.
The Defendant Robert D. Merrill’s appeal is sustained. Remanded to the Superior Court for a revised judgment consistent with this opinion.
. No appeals were taken by the corporate Defendants who were holders of mortgages on the real estate. The Plaintiff had also claimed damages from the Defendants, which the Justice denied her. Her cross-appeal from this denial was abandoned in this Court. Both Defendants had counterclaimed for betterments and the Presiding Justice gave Plaintiff judgment on Defendant Merrill’s counterclaim but made no mention of that of Defendant Poland. Neither Defendant has raised the issue of counterclaims before us and we treat the issues as abandoned. State v. Trott, Me., 289 A.2d 414 (1972).
. R.S.1954, Chap. 92, § 99, 36 M.R.S.A. § 943.
. This limitation no longer prevails. P.L. 1969, Chap. 438, § 3, amending SO M.R. S.A. § 2055.