How does the written description requirement differ for plant patents compared to utility patents?

The written description requirement for plant patents is less stringent than for utility patents. This difference is rooted in the unique nature of plants and the historical challenges of describing them in patent applications. The MPEP cites the Supreme Court’s explanation in Diamond v. Chakrabarty:

“In enacting the Plant Patent Act, Congress addressed both of these concerns. It explained at length its belief that the work of the plant breeder ‘in aid of nature’ was patentable invention. S. Rep. No. 315, 71st Cong., 2d Sess., 6-8 (1930); H.R. Rep. No. 1129, 71st Cong., 2d Sess., 7-9 (1930). And it relaxed the written description requirement in favor of ‘a description … as complete as is reasonably possible.’ 35 U.S.C. § 162.”

Key points about the written description for plant patents:

  • It is relaxed compared to utility patents, requiring a description “as complete as is reasonably possible.”
  • This accommodation recognizes the difficulty in providing a precise written description of a plant’s unique characteristics.
  • The description should still be sufficient to distinguish the new variety from other known plants.
  • Often, the description is supplemented with visual aids like photographs or drawings.

This relaxed standard helps balance the need for clear patent disclosure with the practical challenges of describing living organisms.

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Tags: diamond v. chakrabarty, Patent Disclosure, plant patents, utility patents, Written Description