Funded by U.S. Forest Service (USFS) Rare Plant Partnership

Project Completed: 2024

Institution: Native Plant Trust (NPT)

Evaluating ex situ seed longevity and defining the germination niche of critically imperilled Robbins’ cinquefoil (Potentilla robbinsiana)

Introduction

The NPT and USFS partnered to conduct a seed collection and germination project focused on safeguarding the critically imperilled Robbins’ cinquefoil (Potentilla robbinsiana). The project evaluated seed viability and germination conditions, collected data on optimal growing environments, and included efforts to propagate and outplant the seedlings.

Project Goals

The project aimed to:

• Collect seeds and test germination conditions to identify optimal growth parameters.
• Track long-term seed viability across multiple collections to assess seed bank storage effectiveness.
• Propagate seedlings for reintroduction into the wild by summer 2025.

Key Achievements

The 2023 seed collection yielded 1,338 seeds from 86 maternal lines, with 637 used in experiments and 701 seed-banked for future use. Germination experiments revealed varied optimal temperatures across seed collections, with peak germination typically at 9-14°C. No decline in viability was observed for seeds stored in the seed bank. Germination occurred for all collections evaluated, spanning collection years from 2000 to 2008 (frozen seed) and 2023 (fresh seed).

A total of 56 seedlings are thriving under controlled conditions. Though seedling growth was slower than anticipated, plant-out is planned for summer 2025 to complete the reintroduction phase.