Bartley v. Morgan: Res Judicata Effect of Partial Summary Judgment in Partition Actions and the Bar on Subsequent Adverse Possession Claims

I. Introduction

In Bartley v. Morgan, 2025 NY Slip Op 06590 (2d Dept Nov. 26, 2025), the Appellate Division, Second Department, confronted the intersection of three powerful doctrines in New York real property practice:

Partition between co-owners (siblings holding as tenants in common);
Adverse possession by one co-tenant against the other under RPAPL § 541; and
Res judicata (claim preclusion) based on a prior partial summary judgment in a partition action.

The plaintiff, Carol Bartley, and the defendant, Winston Morgan, are siblings who purchased a Brooklyn property as tenants in common in 1993. Decades later, Morgan brought a partition action. After Morgan obtained partial summary judgment in that case, Bartley attempted—too late—to interpose an adverse possession claim. When leave to amend was denied as untimely and her appeal was not perfected, she tried again by filing a new, separate declaratory judgment action asserting adverse possession.

The majority (Barros, J.P., Brathwaite Nelson, and Ventura, JJ.) held that the new adverse possession action was barred by res judicata, because the partition action had resulted in an order granting summary judgment on the complaint (to the extent of appointing a referee) and Bartley could have raised adverse possession there in a timely way. The court affirmed the Supreme Court’s order denying Bartley’s motion for summary judgment and granting Morgan’s cross-motion to dismiss.

Justice Janice A. Taylor concurred in part and dissented in part. She agreed that Bartley was not entitled to summary judgment on adverse possession, but vigorously rejected the majority’s use of res judicata, arguing there had been no final determination in the partition action sufficient to trigger claim preclusion. In her view, treating the partial summary judgment order as res judicata was doctrinally unsupported, inconsistent with partition procedure, and potentially unjust.

The decision thus sets (or at least signals) an important Second Department precedent: a partial summary judgment in a partition action that appoints a referee to determine the parties’ interests may be treated as a merits determination sufficient to bar later, separate actions—such as adverse possession claims—that could have been raised earlier. The dissent highlights the tension this creates with traditional finality principles and with the equitable nature of partition proceedings.

II. Summary of the Opinion

A. Procedural Posture

The appeal arose from an order of the Supreme Court, Kings County (Wade, J.), dated November 9, 2023, which:

Denied Bartley’s motion for summary judgment declaring her the owner of the property by adverse possession; and
Granted Morgan’s cross-motion for summary judgment dismissing the complaint as barred by res judicata.

Bartley appealed. The Appellate Division affirmed the order, with costs.

B. Majority Holding

The majority held:

An order granting summary judgment is a disposition “on the merits” with preclusive effect (citing Genaro Partners, Inc. v Somwaru and Cox v Hubbard).
Under New York’s transactional approach to res judicata, a final disposition in an earlier action bars all claims arising from the same transaction that were or could have been raised, even under different theories or seeking different relief (citing Panagiotou v Samaritan Vil., Inc. and Henry Modell & Co. v Minister, Elders & Deacons).
The prior partition action, in which Morgan obtained summary judgment directing the appointment of a referee under RPAPL § 915 to determine the parties’ rights and whether a sale was necessary, constituted such a disposition on the merits.
Bartley could have raised adverse possession as a defense and counterclaim in the partition action, and indeed attempted to do so but was denied leave as untimely; her failure to assert it in a timely manner means she cannot bring a new action to litigate that claim now.
A judgment in her favor in this new action would impair the rights or interests established in the partition action, so the second action is barred by res judicata.

Accordingly, the court:

Upheld the dismissal of Bartley’s complaint; and
Left intact the earlier partition proceedings, including the prior grant of summary judgment for partition in Morgan’s favor.

C. Dissent (Taylor, J.)

Justice Taylor would have:

Affirmed the denial of Bartley’s motion for summary judgment on adverse possession; but
Reversed the grant of Morgan’s cross-motion, holding that res judicata did not apply and that the complaint should not have been dismissed.

Her key points:

Res judicata requires a final determination on the merits (citing Landau, P.C. v LaRossa, Mitchell & Ross and Manko v Gabay).
In partition cases, there is no such final determination until the entry of the interlocutory judgment under RPAPL § 915 and, ultimately, a final judgment under RPAPL § 927 (citing Clarke v Clarke).
Here, no interlocutory or final judgment had been entered when Bartley commenced this new action; only an order appointing a referee had been issued. Under Brown v Cleveland Trust Co., “an interlocutory judgment … is never res adjudicata,” and the order at issue was even short of an interlocutory judgment.
The cases the majority relies on all involved prior actions resolved by summary judgment dismissing the complaint, unlike this partition order, which merely advanced the proceeding procedurally.
Because partition is an equitable remedy and may ultimately be denied on equitable grounds—even after a referee’s hearing—using res judicata at this stage risks significant injustice to Bartley, who has lived in and maintained the property for more than 30 years.
Nonetheless, Bartley did not establish her entitlement to summary judgment on adverse possession because there are triable issues as to whether she had a “reasonable basis” to believe she owned the property exclusively for the statutory period (citing Buckheit v Aiken).

III. Factual and Procedural Background

A. The Property and the Co-Ownership

In 1993, the Brooklyn property was conveyed to Bartley and Morgan as tenants in common by deed dated March 12, 1993.
The purchase price was $235,000. Morgan contributed $23,500 (approximately 10%) to the initial purchase price.
After closing, Bartley:
- Moved into the property;
- Paid off the mortgage; and
- Continued to live in the property for more than 30 years.
According to Bartley (per the dissent), she repaid roughly half of Morgan’s initial contribution and Morgan:
- Never lived at the property; and
- Never contributed to mortgage payments or upkeep for three decades.

B. The Partition Action (the “Prior Action”)

Filing and Relief Sought In February 2019, Morgan commenced an action for:
- Partition and sale of the property; and
- An accounting of all rental income Bartley had collected.
Bartley’s Defense Bartley responded that:
- The property was not jointly owned in a substantive sense because:
  - There was never any mention of an equal partnership; and
  - Morgan made no contribution to care and maintenance.
She did not initially plead adverse possession, nor did she assert that she had ousted Morgan as co-tenant.
Morgan’s Summary Judgment Motion Morgan moved for summary judgment on the complaint. In an order dated November 4, 2021, as amended on December 10, 2021, the Supreme Court:
- Granted Morgan’s motion “to the extent” of directing that a referee be appointed, inter alia, to:
  - Conduct a hearing to determine the “right, share, and interest” of each party in the property; and
  - Determine whether a sale was necessary because partition could not be made without prejudice to the parties (see RPAPL § 915).
The complaint was not dismissed; the proceeding was advanced to the refereeing phase mandated by statute.
Attempt to Add Adverse Possession in the Partition Action On November 24, 2021, shortly after the summary judgment order, Bartley moved:
- For leave to amend her answer to add an affirmative defense and a counterclaim of adverse possession under RPAPL § 541.
In an order dated August 19, 2022, the Supreme Court:
- Denied leave to amend, deeming the motion untimely.
Bartley appealed the denial of leave to amend, but:
- Her appeal was not perfected;
- The appeal was deemed dismissed.

C. The New Adverse Possession Action

Commencement of New Action In November 2022, Bartley commenced a new, separate action seeking:
- A judgment declaring that she is the sole owner of the property by adverse possession.
Summary Judgment Motions in the New Action
- Bartley moved for summary judgment declaring her to be the owner by adverse possession.
- Morgan cross-moved for summary judgment dismissing the complaint, arguing that:
  - The new action was barred by res judicata because the partition action had already resulted in a summary judgment order on the complaint.
Supreme Court’s 2023 Order By order dated November 9, 2023, the Supreme Court:
- Denied Bartley’s motion for summary judgment on adverse possession; and
- Granted Morgan’s cross-motion for summary judgment dismissing the complaint based on res judicata.
Appeal to the Appellate Division Bartley appealed from the November 9, 2023 order, leading to the Second Department’s decision in Bartley v. Morgan.

IV. Legal Issues

The core issues addressed by the Appellate Division are:

Res Judicata / Claim Preclusion Does the partial summary judgment order in the partition action—directing the appointment of a referee to determine the parties’ shares and whether a sale is necessary—constitute a “final determination on the merits” sufficient to bar a subsequent, separate action for adverse possession arising from the same property and relationship?
Scope of Transactional Res Judicata Under New York’s transactional analysis, if a claim like adverse possession could have been raised in the partition action, is Bartley forever barred from litigating it in a separate proceeding once summary judgment has been granted in favor of partition?
Adverse Possession Standards Between Co-Tenants Although not resolved on the merits, the dissent engages with whether Bartley made a sufficient showing to be granted summary judgment on adverse possession, particularly on the element of a reasonable belief that she owned the property exclusively.

V. Precedents Cited and Their Influence

A. Res Judicata and Transactional Analysis

1. Genaro Partners, Inc. v Somwaru, 200 AD3d 858

Quoted by the majority for the proposition that:

“An order granting a summary judgment motion is on the merits and has preclusive effect.”

Genaro involved a prior action resolved by summary judgment dismissing the complaint. The Second Department there emphasized that once a party obtains summary judgment in such a way, the determination operates as a judgment on the merits for res judicata purposes. The majority in Bartley uses this to argue that the summary judgment order in the partition action is similarly “on the merits.”

2. Cox v Hubbard, 115 AD3d 783

Also cited to reinforce that summary judgment is a disposition on the merits with preclusive effect. As with Genaro, the context was an order granting summary judgment which fully disposed of the earlier action.

3. Panagiotou v Samaritan Village, Inc., 88 AD3d 779

Quoted by the majority for New York’s transactional approach to res judicata. Under this approach:

“Once a claim is brought to a final conclusion, all other claims arising out of the same transaction or series of transactions are barred, even if based upon different theories or if seeking a different remedy.”

This principle is central: the bar applies to all claims arising from the same nucleus of operative fact, not merely those actually litigated. The majority applies this to say that Bartley’s adverse possession claim—arising from the same co-tenancy and property that underlie the partition action—should have been brought previously and is now barred.

4. Henry Modell & Co. v Minister, Elders & Deacons of Ref. Prot. Dutch Church of City of N.Y., 68 NY2d 456

The majority invokes Henry Modell for this proposition (from footnote 2):

New York does not “permit a party to remain silent in the first action and then bring a second one on the basis of a preexisting claim for relief that would impair the rights or interests established in the first action.”

This quotation crystallizes the policy rationale: parties must bring all their available claims and defenses at once if they arise from the same transaction, especially where withholding them would undermine the finality or integrity of the first action’s result. The majority frames Bartley as having done exactly what Henry Modell forbids.

5. O’Brien v City of Syracuse, 54 NY2d 353

O’Brien is one of the Court of Appeals’ foundational cases on res judicata in New York. It establishes that:

Res judicata bars claims that were or could have been raised in the prior action; and
New legal theories are not enough to escape the bar if they are grounded in the same transaction.

The majority cites O’Brien to emphasize that Bartley’s failure to timely assert adverse possession—although she clearly could have tried earlier—now forecloses her separate lawsuit.

6. Myers v Meyers, 121 AD3d 762

Cited by both the majority and the dissent. Myers applies transactional res judicata, reinforcing that:

Claims that could have been raised in the prior action are barred; and
The doctrine is designed to prevent piecemeal litigation between the same parties over the same subject matter.

The majority uses Myers to support preclusion; the dissent uses it more broadly, alongside other authorities, to stress the need for a final determination before res judicata applies.

7. Hae Sheng Wang v Pao-Mei Wang, 96 AD3d 1005

Cited by the majority at the end, and by the dissent for its articulation of res judicata’s rationale:

“The rationale for the doctrine is that a party who has been given a full and fair opportunity to litigate a claim should not be allowed to do so again; allowing relitigation would undermine the interest of the community and the litigants in finality.”

The dissent leans on this fairness-based description to argue that Bartley has not yet had a full and fair opportunity to litigate adverse possession because the partition action remains incomplete and her adverse possession theory has never been adjudicated on the merits.

8. Matter of Greenville Fire Dist. v Town Bd. of the Town of Greenburgh, 202 AD3d 956; Landau, P.C. v LaRossa, Mitchell & Ross, 11 NY3d 8; Manko v Gabay, 175 AD3d 484

These cases, cited primarily in the dissent, reinforce that:

Res judicata requires a judgment on the merits and a final determination.
Landau warns that misapplication of res judicata “has the potential to work considerable injustice.”

Justice Taylor uses these to ground her critique that the partition action had not yet reached a procedurally final stage, and that using res judicata at this point risks the kind of injustice Landau cautions against.

9. Matter of Haberman v Zoning Bd. of Appeals of City of Long Beach, 119 AD3d 789

Cited in the dissent as part of the broader set of cases explaining that res judicata bars not only claims actually litigated but also those that could have been raised in the prior litigation—again, contingent on a valid final judgment.

10. Piscionere v Gori, 2025 NY Slip Op 05710

Cited by the majority as a recent application of the rule that a second action is barred where a judgment in that second case would “impair the rights or interests established in the first action.” Although details are not provided in the slip opinion here, the reference suggests:

The Second Department is consistently enforcing res judicata where a subsequent claim threatens to undercut an earlier merits-based determination between the same parties over the same subject matter.

B. Partition Procedure and RPAPL

1. RPAPL §§ 911, 915, 927 and Clarke v Clarke, 227 AD3d 659

The dissent provides a detailed and accurate account of New York partition procedure:

Before directing partition or sale, the court must:
- Determine the rights, shares, or interests of the parties; and
- Determine whether physical partition can be made without great prejudice, or whether a sale is necessary (RPAPL §§ 911, 915).
These determinations are embodied in an interlocutory judgment under RPAPL § 915.
Only thereafter is a final judgment entered (RPAPL § 927) to effectuate the partition or sale and distribution.

Clarke v Clarke is cited for the propositions that:

“Before a partition or sale may be directed, a determination must be made as to the rights, shares, or interests of the parties, and whether partition may be had without great prejudice.”
Such determinations must be included in the interlocutory judgment, along with directions for sale or physical partition.

The dissent relies on this structure to argue that, at the time Bartley filed her new action, the partition case was midstream: no interlocutory or final judgment had yet been rendered, so there was no judgment capable of supporting res judicata.

2. Brown v Cleveland Trust Co., 233 NY 399; Morley v Quinones, 208 AD2d 813

Brown, a Court of Appeals case, is invoked for the sweeping statement that:

“An interlocutory judgment … is never res adjudicata.”

The dissent uses this as the backbone of its argument: if even an interlocutory judgment in a partition case (which had not yet been entered here) cannot support res judicata, then surely an order merely appointing a referee to conduct a hearing (a step preliminary to that interlocutory judgment) cannot be treated as having preclusive effect.

Morley v Quinones is cited “cf.” to illustrate the difference between interlocutory judgments and final judgments in partition-like or related contexts.

3. Equitable Nature of Partition: Goldberger v Rudnicki, 94 AD3d 1048; Ripp v Ripp, 38 AD2d 65, affd 32 NY2d 755; Stressler v Stressler, 193 AD2d 728

Justice Taylor stresses that:

“The right to partition is not absolute” and “is always subject to the equities between the parties.”

She cites:

Goldberger v Rudnicki – partition decisions must consider equitable factors between co-owners.
Ripp v Ripp – which supports the principle that equitable defenses and circumstances can limit or even defeat a formal right to partition.
Stressler v Stressler – where, after determining the parties’ rights and interests, the court concluded that the equities favored dismissal of the partition action.

These authorities highlight a critical point: even after a referee’s findings and interlocutory steps, a court may still deny partition altogether on equitable grounds. This fact underlines the dissent’s concern: if the partition action might ultimately be dismissed, then barring Bartley’s adverse possession claim now (before that equitable determination) is premature and potentially unjust.

C. Adverse Possession and RPAPL § 541

1. RPAPL § 541: Adverse Possession by a Co-Tenant

RPAPL § 541 (specifically invoked by Bartley) governs adverse possession in a co-tenancy context. While the Opinion text does not quote the statute, its basic principles (consistent with New York law) are:

Possession by one tenant in common is presumed to be in right of all co-tenants (a permissive possession), not hostile;
To convert such possession into adverse possession, the occupying co-tenant must:
- “Oust” the other co-tenants or
- Otherwise unequivocally act in a manner hostile to the co-tenancy for the statutory period.

Recent case law has incorporated a “reasonable basis for belief of ownership” standard into the hostility element (discussed in Buckheit v Aiken, cited by the dissent).

2. Buckheit v Aiken, 232 AD3d 842

The dissent cites Buckheit for the proposition that an adverse possessor must show, among other things, that they had a reasonable basis for their belief that the property belonged to them exclusively for the required period. Applying that standard, Justice Taylor concludes:

Bartley made a “strong showing” on several adverse possession elements (long, exclusive occupancy; payment of mortgage; maintenance);
But she did not eliminate all triable issues of fact regarding whether she reasonably believed the property belonged solely to her;
Therefore, she was not entitled to summary judgment on adverse possession.

This is important because it shows that even the dissent is not prepared to grant Bartley the relief she seeks on the merits at this stage; the difference is over whether her claim may proceed at all (res judicata vs. no res judicata), not over whether she has already proven adverse possession.

VI. The Court’s Legal Reasoning

A. Majority Opinion

1. Characterizing the Prior Order as a “Disposition on the Merits”

The majority begins from the general principle: summary judgment is a disposition on the merits with preclusive effect. Citing Genaro and Cox, the court notes:

“An order granting a summary judgment motion is on the merits and has preclusive effect.”

In the prior partition action:

Morgan moved for summary judgment “on the complaint.”
The Supreme Court granted that motion “to the extent” of appointing a referee to determine the parties’ shares and whether partition in kind was possible without prejudice.

The majority treats this as:

A merits-based adjudication in Morgan’s favor—at least as to his entitlement to pursue partition and the need for further judicial fact-finding under RPAPL § 915.

2. Applying Transactional Res Judicata

From there, the majority applies New York’s transactional analysis:

Under Panagiotou and O’Brien, once a claim is finally resolved, all claims arising out of the same “transaction or series of transactions” are barred, including those based on different theories or seeking different forms of relief.
Under Henry Modell, a party may not stand silent and then later bring a second action that would impair the rights or interests established in the first.

Here:

The “transaction” is the parties’ co-ownership of the property and their respective claims to title, possession, and economic benefit.
The partition action already squarely put at issue ownership, shares, and equitable rights to the property.
Adverse possession is a competing claim to exclusive ownership of that same property, directly undermining the premise of shared ownership and partition.
Bartley could have asserted adverse possession as a defense and counterclaim in the partition action; indeed, she tried—albeit belatedly—by moving to amend.

Accordingly, the majority concludes:

“Here, this action is barred by the doctrine of res judicata, since a judgment in favor of Bartley would impair the rights or interests established in the prior action.”

3. Emphasis on Procedural Default

A crucial part of the majority’s rationale is Bartley’s procedural default:

She failed to timely assert the adverse possession defense in the partition action; and
Her attempt to amend was denied as untimely, and her appeal from that denial was not perfected.

The majority frames this in classic res judicata terms:

“Since Bartley failed to timely assert a defense of adverse possession in the prior action, although she could have done so had she acted in a timely manner, this claim is now barred.”

In other words, the law does not reward a litigant’s failure to comply with procedural rules by allowing them to “repackage” the same underlying claim in a separate lawsuit.

4. Collateral Review Concern

The majority also stresses that the new action is, functionally, an impermissible collateral attack:

“By commencing this action, Bartley impermissibly sought collateral review of the determination awarding summary judgment for partition in the prior action.”

Any declaration that Bartley is the sole owner by adverse possession would directly contradict:

The prior order’s implicit recognition of Morgan’s ownership interest sufficient to support partition; and
The ongoing judicial process to define the parties’ respective shares and interests via the referee’s hearing.

5. Result

On this basis, the majority:

Affirms denial of Bartley’s summary judgment motion (for failure to establish entitlement to judgment as a matter of law on adverse possession—though the majority does not analyze that element extensively); and
Affirms the grant of Morgan’s cross-motion, holding the entirety of Bartley’s complaint barred by res judicata.

B. Dissenting / Concurring Opinion (Taylor, J.)

1. Requirement of a Final Determination on the Merits

Justice Taylor’s core doctrinal disagreement concerns the concept of finality:

Res judicata applies only where there has been a “final determination on the merits” (citing Landau, Manko, and Greenville Fire Dist.).
At the time Bartley commenced this action:
- The court in the partition action had not yet determined “the rights, shares, or interests” of the parties; and
- Neither the interlocutory judgment (RPAPL § 915) nor final judgment (RPAPL § 927) had been entered.

Thus, the prior action had not reached the stage at which claim preclusion could attach.

2. Interlocutory Judgments and Brown v Cleveland Trust Co.

Justice Taylor emphasizes:

“The Court of Appeals has held that ‘an interlocutory judgment … is never res adjudicata.’”

(Brown v Cleveland Trust Co., 233 NY 399, 405).

She then notes:

Not only had no “final” judgment been entered;
Even the statutorily contemplated interlocutory judgment had not yet been entered;
The order relied upon by the majority merely appointed a referee—an even earlier procedural step than an interlocutory judgment.

If an interlocutory judgment itself is not res judicata, she argues, it is doctrinally unsound to give preclusive effect to a pre-interlocutory order appointing a referee.

3. Distinguishing the Majority’s Case Law

Justice Taylor agrees that, as a general matter, an order granting summary judgment is often “on the merits” and can support res judicata. But she insists that the majority’s reliance on cases like Genaro, Myers, Cox, and Panagiotou is misplaced because:

In those cases, the prior action had been resolved by an order granting summary judgment that dismissed the complaint.
In Bartley, the order did not dismiss Morgan’s complaint; it simply appointed a referee to carry out the statutory fact-finding in a partition case.

Thus, the key feature present in prior res judicata cases—a true final determination fully disposing of a claim or action—is missing here.

4. The Equitable Nature of Partition and Potential Injustice

Justice Taylor expresses concern about the potential inequity in barring Bartley’s adverse possession claim before the partition action fully runs its course:

Partition is an equitable remedy, and the right to partition is “not absolute” (citing Clarke, Goldberger, Ripp).
Courts may, and sometimes do, dismiss partition actions altogether after considering the equities (see Stressler).
Given the facts alleged—Bartley’s 30+ years of occupancy, mortgage payments, maintenance, and Morgan’s minimal economic and practical engagement—an equitable dismissal of Morgan’s partition action remains possible.

Against this backdrop, Justice Taylor warns:

“Under the circumstances, the application of res judicata by my colleagues in the majority, which I submit is misplaced, ‘has the potential to work considerable injustice’ to Bartley and her ability to stay in her home of more than 30 years (Landau, P.C. v LaRossa, Mitchell & Ross, 11 NY3d at 14).”

Her critique is thus both doctrinal (finality, interlocutory judgments) and equitable (risk of unjust outcome).

5. Denial of Bartley’s Motion on the Merits of Adverse Possession

Despite vehement disagreement on res judicata, Justice Taylor agrees with the Supreme Court that Bartley is not entitled to summary judgment on adverse possession:

She finds Bartley has made a “strong showing” on many adverse possession elements (long-term, exclusive occupancy; contributions to mortgage and upkeep).
But under Buckheit v Aiken, Bartley still needed to eliminate factual issues as to whether she had a reasonable basis to believe she owned the property exclusively.
Because that element remains factually disputed, summary judgment in Bartley’s favor would be improper.

Thus, the dissent would:

Affirm the denial of Bartley’s summary judgment motion; but
Reverse the grant of Morgan’s cross-motion and allow Bartley’s adverse possession claim to proceed to adjudication on the merits.

VII. Complex Concepts Simplified

A. What Is Res Judicata (Claim Preclusion)?

Res judicata, or claim preclusion, prevents parties from re-litigating a claim that has already been finally resolved between them. In New York:

It applies when:
- The earlier action resulted in a final judgment on the merits;
- The parties (or those in privity) are the same; and
- The later claim arises from the same transaction or series of transactions as the earlier case.
It bars:
- Claims that were actually raised; and
- Claims that could have been raised in the earlier action, even based on different legal theories or seeking different relief.

Here, the dispute is not about the identity of parties or the factual transaction (both are clearly the same), but about:

Whether the prior partition order was sufficiently final to trigger res judicata; and
Whether Bartley’s adverse possession claim is a claim that “could have been raised” in that earlier action (the majority says “yes,” the dissent does not dispute the theoretical ability but questions preclusion at this procedural stage).

B. Summary Judgment and Partial Summary Judgment

Summary judgment is a procedural device for resolving a case without trial when there is no genuine issue of material fact and the moving party is entitled to judgment as a matter of law.

A court may:
- Grant summary judgment on the entire complaint or on specific claims or issues;
- Issue partial summary judgment, which may leave some issues for trial or further proceedings.

In Bartley:

Morgan’s summary judgment motion in the partition action was granted “to the extent” of appointing a referee, a form of partial summary judgment establishing certain entitlements and referring the rest for further proceedings.
The majority treats this as sufficiently “on the merits” to have preclusive effect.
The dissent objects that this order is still a pre-final, procedural step in a unique statutory regime and cannot support res judicata.

C. Partition Actions in New York (RPAPL Article 9)

A partition action is brought when co-owners (e.g., tenants in common) cannot agree on what to do with jointly owned real property. Key points:

The plaintiff seeks a court order to:
- Physically divide the property (partition in kind), or
- Sell the property and divide the proceeds (partition by sale).
Under RPAPL §§ 911, 915, 927:
- The court must first determine each party’s “rights, shares, or interests” and whether partition in kind is possible without great prejudice.
- These findings are embodied in an interlocutory judgment (RPAPL § 915).
- Only after this interlocutory judgment is a final judgment entered, directing sale or division and distribution (RPAPL § 927).
Partition is an equitable remedy:
- The court may consider fairness, contributions, and equities between the parties; and
- It may deny or adjust partition to prevent inequitable outcomes.

D. Adverse Possession Between Co-Tenants (RPAPL § 541)

Adverse possession is a doctrine allowing someone who occupies property openly, continuously, and under a claim of right for a statutory period to become the legal owner, even as against the record owner.

Between co-tenants (like tenants in common), the doctrine is stricter:

Possession by one co-tenant is presumed to be for the benefit of all co-tenants.
To gain title by adverse possession, the occupying co-tenant must:
- Oust the other co-tenant, or
- Otherwise clearly and unequivocally act in a manner inconsistent with the other’s ownership rights;
- Maintain such adverse, hostile possession for the statutory period (typically ten years under New York law); and
- (Under modern standards) demonstrate a reasonable basis for believing in sole ownership during that period.

In this case:

Bartley appears to have a potentially strong factual argument (decades of exclusive occupation and economic support);
But the dissent notes unresolved factual questions about her state of mind—did she reasonably believe she alone owned the property, especially given Morgan’s name on the deed and his initial contribution?

VIII. Impact and Significance

A. Doctrinal Impact: Expansion of Res Judicata in Partition Context

The majority in Bartley effectively extends the reach of res judicata into the earlier, interlocutory stages of partition actions:

By treating a partial summary judgment order (appointing a referee under RPAPL § 915) as a “disposition on the merits” sufficient for claim preclusion, the court gives that order greater preclusive effect than traditional partition doctrine might suggest.
This position sits in tension with:
- Brown v Cleveland Trust Co., which declares interlocutory judgments to be “never res adjudicata”; and
- The RPAPL’s procedural architecture, which contemplates further judicial action and equitably informed decisions after the referee’s report.

The dissent highlights this tension and frames the majority’s move as “seemingly unprecedented.” Whether other Departments will follow this approach, and how the Court of Appeals might view such an expansion of res judicata, remains to be seen.

B. Practical Lessons for Litigators and Property Owners

Raise All Available Claims and Defenses Early The case sends a strong message: if you are involved in a partition or any real property dispute:
- Assert all potentially viable claims and defenses (e.g., adverse possession, constructive trust, laches, equitable defenses) in the first action;
- Move to amend promptly if new theories emerge; and
- Do not rely on being able to bring a separate future action on those theories.
Timeliness and Appellate Practice Matter Bartley’s position was undermined by:
- Her failure to timely move to amend (leading to denial on timeliness grounds); and
- Her failure to perfect appeals from adverse interlocutory orders.
These procedural lapses gave the majority a firm basis to say she “could have” raised adverse possession in the prior action but did not.
Partition Actions Now Carry Increased Preclusive Risk Under Bartley, litigants should assume that:
- Once the court grants summary judgment in a partition case—even partially—res judicata may attach to all claims arising from the co-ownership relationship; and
- Later attempts to assert ownership theories like adverse possession in separate actions may be barred.
Family and Co-Ownership Disputes: Stakes Are High Family co-ownership disputes often involve long, informal arrangements with uneven financial contributions and occupancy. Bartley illustrates:
- How formal legal rights (title as tenants in common) can clash with long-term practical realities (one sibling living in and paying for the property); and
- How procedural missteps can foreclose potentially meritorious equitable or adverse possession claims.

C. Potential Future Developments

The case raises questions that may prompt further appellate clarification:

Will other panels or Departments treat pre-interlocutory partition orders as res judicata?
How will courts reconcile Brown v Cleveland Trust and partition-specific statutes with general civil practice rules on summary judgment finality?
Could the Court of Appeals revisit the scope of res judicata in multi-stage equitable proceedings like partition where interlocutory orders set the framework but do not fully resolve rights?

Until such clarification, practitioners in the Second Department must assume Bartley reflects binding precedent: a partial summary judgment in a partition case can have full claim-preclusive effect on later actions between the same parties about the same property.

IX. Conclusion

Bartley v. Morgan is a significant Second Department decision at the crossroads of property law, civil procedure, and equity. The majority:

Applies New York’s transactional res judicata doctrine robustly to a partition action;
Treats a partial summary judgment order appointing a referee as a merits-based disposition sufficient to bar subsequent litigation between the same siblings over ownership of the same property; and
Holds that Bartley’s belated attempt to assert adverse possession in a separate declaratory judgment action is barred because she could and should have raised that theory in the earlier partition proceeding.

The dissenting opinion forcefully counters that:

Res judicata requires a final determination on the merits, which had not occurred in the partition action; and
Applying claim preclusion at this pre-interlocutory stage is inconsistent with both partition procedure under RPAPL and the Court of Appeals’ guidance in Brown and Landau, and risks serious injustice to a long-term occupant like Bartley.

Although the court did not decide the adverse possession claim on its substantive merits, the ruling effectively ends Bartley’s ability to litigate that theory in a separate action. The case stands as a cautionary precedent: in New York’s Second Department, parties in partition and similar property disputes must assume that once partial summary judgment has been granted, any claim they could have raised but did not—such as adverse possession—may be forever lost.

In the broader legal context, Bartley v. Morgan underscores the power and reach of res judicata, especially when combined with New York’s transactional approach. It also highlights the tension between rigid procedural finality and the equitable, often fact-sensitive nature of real property disputes within families and co-tenancies. How that tension will be resolved in future cases, and whether higher courts will refine or limit Bartley’s reach, will be of significant interest to real property and civil procedure practitioners alike.