## Facts

- Woodland Trust, assignee of U.S. Patent No. 4,763,440, accused Flowertree Nursery, Inc. and Ivy J. Winslett of infringing a patent directed to freeze protection for foliage plants using a covering and coordinated ground-level and elevated sprinkling to form insulating ice.
- The application was filed July 1, 1983, and the patent issued August 16, 1988.
- Flowertree asserted invalidity under 35 U.S.C. §§ 102(a), 102(b), and 103, alleging similar systems had been used at nurseries operated by Joseph Burke and by William Hawkins (a Flowertree owner) in the 1960s–1970s, ending by roughly 1976–1978.
- Flowertree relied primarily on testimony from four witnesses who were prior users or were related to, employed by, or friends of persons alleged to have used the earlier systems.
- No meaningful contemporaneous documentary or physical evidence (e.g., photographs, drawings, invoices, business records) was produced to corroborate the alleged prior uses.

## Issues

1. Whether uncorroborated oral testimony about long-past events, particularly from interested or closely associated witnesses, can constitute clear and convincing evidence of prior knowledge and use sufficient to invalidate an issued patent under 35 U.S.C. § 102.
2. Whether the alleged nursery systems constituted prior art that anticipated the patent claims or otherwise rendered them invalid.

## Decision

- The Federal Circuit reversed the district court’s judgment that the patent was invalid for prior knowledge and use by others.
- The court held that uncorroborated oral testimony, especially from interested persons recalling remote events, is insufficient by itself to meet the clear and convincing evidence standard for invalidating an issued patent on prior-use grounds.
- The case was remanded for further proceedings consistent with the appellate ruling.

## Legal Principles

- An issued patent is presumed valid; invalidity must be proven by clear and convincing evidence.
- Alleged prior public knowledge or use cannot be established solely through uncorroborated oral recollections of long-ago events, particularly where witnesses are interested or closely connected to the alleged prior users.
- Corroboration is assessed under a rule-of-reason approach that considers factors such as witness relationships, lapse of time, internal consistency and detail, impeachment, familiarity with the technology, plausibility of the asserted activities, and the expected existence of commercial records.
- The absence of documentary or physical evidence from purported commercial activity weighs strongly against finding prior use proven to the required evidentiary standard.

## Conclusion

The Federal Circuit rejected a patent invalidity finding that rested largely on uncorroborated, decades-old witness recollections, holding that prior knowledge and use under § 102 must be proven with clear and convincing evidence supported by reliable corroboration, not oral testimony alone.


Woodland Trust v. Flowertree Nursery, Inc., 148 F.3d 1368 (Fed. Cir. 1998)