Nature scrapbook: Moccasin flowers

Rising from carpets of fallen pine needles, moss and lichens, the moccasin flower is the belle of the ball in June among the blooms of mixed and evergreen forests with sandy soil. Also known as the pink lady’s slipper, it’s the preeminent orchid of the Canadian Shield, and indeed cottage country’s only relatively common member of its intriguing and highly esteemed family.

Made to order

With more than 22,000 species, about 60 of them occurring in Ontario, orchids are the second largest plant family on Earth, displaying unique, exquisitely intricate and highly varied floral structures. Some have co-evolved to be pollinated by a single insect species. In the moccasin flower’s case, it’s often a bumblebee queen, who visits the plant before her first batch of workers pupate and take over her foraging duties.

Ingenious deceit

All orchids bear three petals, one of which is a greatly modified central “lip,” which serves as a landing pad for pollinating insects. Bumble queens are lured by the scent and promise of sweet nectar into the large hollow pouch, or “slipper.”

Once inside, the big bee actually finds little nectar, but the edges of the entrance won’t bend backwards to let her out. Instead, she must follow a narrow passage leading to the female flower part (where, were she carrying any pollen, it would be deposited). Beyond that she passes by the male parts, one in each of a pair of openings at the top of the flower, each with a precisely placed glob of pollen, which sticks to her back where she can’t reach to clean off.

Light and lean

In some areas, only some two to 10 per cent of moccasin flowers are pollinated each season, but a fertilized plant produces a single erect, green capsule which splits in autumn to release tens of thousands of minute, dust-like seeds—each consisting of about 100 cells—to the wind.

Underground connection

Orchid seeds lack a well-formed embryonic seedling or the significant store of food that comprises the largest portion of the seeds of most other plants. When they germinate, orchid seeds must link with the threads of a symbiotic fungus that provides them with the nutrients they need to survive. In return, the plant sends the fungus sugars produced through photosynthesis after it sprouts leaves. But a pink lady’s slipper commonly remains unseen as a miniscule root bulb for its first three or four years and takes nine to 16 years to flower, though a colony may persist for as long as the forest in which it grows.

Number of seeds produced per plant, per season

White Trillium 9-10
White water lily 600-700
Queen Anne’s lace About 10,000
Moccasin flower 50,000-60,000