US Plant Patent PP21184
Hokuto-18
Bunashimeji mushroom plant named ‘Hokuto-18’
UNDER PATENT
Still under patent. Protection ends January 29, 2028.
Twenty years from the filing date would end on August 18, 2025. This patent earned 894 days of term adjustment for delay at the Patent Office, which is why it runs longer.

The record
- Patent number
- PP21184
- Filed
- August 18, 2005
- Granted
- August 3, 2010
- Expires
- January 29, 2028
- Assignee
- HOKUTO CORP
- Inventor
- YAMAZAKI MIZUE; OKU TAKESHI; INATOMI SATOSHI; NAMBA KENJI
Abstract
A new and distinct variety of mushroom plant of Bunashimeji mushroom, Hypsizigus marmoreus , named ‘Hokuto-18’, is cultivated by gathering and repeated breeding of fungal strains having dominant traits. This new and distinct variety has good qualitative character and appearance, good keeping quality and storage life and delicious tasting and is exquisite in stability, reproducibility and uniformity when being produced.
Show the legal claimThe single numbered claim as granted — the legal text that defines what this patent covers.
1. A new, distinct variety of Bunashimeji mushroom as substantially illustrated or described in the specification.
Read the full patent: US Plant Patent PP21184 in full — the complete specification, every figure, and the file history.