Evolution of Flammulina Velutipes Basidiocarp Size with Respect to Relative Humidity

ABSTRACT

Populations of Flammulina velutipes adapted to drier environments produce basidiocarps that emerge from their substrate with pilei and stipes 24% broader and pilei 19% thicker than the basidiocarps of populations of the same species adapted to wetter environments. The dry-tolerant isolates had more surface area exposed to evaporative loss, a higher percentage of water in their tissues, and a larger initial water allocation. Both wet-specialist and dry-tolerant population isolates are genetically programmed for large ultimate size under saturated water conditions; however, under water stress conditions, expanding and thickening the pileus too late reduces spore production fivefold for the wet-specialist populations.

Key Words:

• adaptation
• Agaricales development