In a manner relating to or characteristic of cleistogamous reproduction; by self-pollination within closed flowers.
From cleistogamous plus -ly adverbial suffix. The adverbial form allows description of how a plant reproduces or behaves in a way characteristic of cleistogamy.
This adverb lets scientists describe the actual reproductive behavior—when we say a plant 'reproduces cleistogamously,' we're noting that this particular flower event involved closed-flower self-pollination rather than open-flower cross-pollination.
Complete word intelligence in one call. Free tier — 50 lookups/day.