Triphora trianthophoros (Sw.) Rydb.

Three Bird Orchid

© DETenaglia

Family - Orchidaceae

Habit - Perennial forb from tuberous root bases and stolons (the tubers forming at the tips of the stolons).

Stems - To +15cm tall, herbaceous, erect, fleshy, purplish at base, glabrous, forming small colonies.

Leaves - Alternate, clasping, scalelike below, becoming ovate above, acute, entire, glabrous, to +/-1.2cm long, +/-9mm broad.

© DETenaglia

Inflorescence - Single axillary flowers, typically 3-4 per plant. Flowers erect (but nodding while in bud). Pedicels erect, to 1cm long, glabrous.

Flowers - Whitish, to 2cm long. Floral tube -5mm long, glabrous. Petals 3. Lower petal white, 1.4cm long, greenish, with a bearded strip internally, 3-lobed. Central lobe to +5mm long, with eros margins. Lateral lobes rounded, 2-3mm long. Upper petals linear, white, 1.6cm long, 2-3mm broad. Column 1.1cm long, green at the base, white apically, glabrous. Pollinia purple. Pollen pinkish-purple. Ovary inferior, unilocular. Placentation parietal. Sepals 3, white, glabrous, 1.8cm long, 2-3mm broad, subfalcate, cupped. Petals and sepals sometimes with a purplish tinge.

	Flower.
© DETenaglia

	Side view.
© DETenaglia

Fruit - Capsules nodding during development, erect at maturity, 10-15 mm long, elliptic, strongly ribbed. Seeds numerous, dustlike.

	Immature fruit.
© SRTurner

	Mature fruit nearing dehiscence.
© SRTurner

Flowering - July - October.

Habitat - Mesic woods, ravines, stream valleys, bottomland forests.

Origin - Native to the U.S.

Lookalikes - None when flowering.

Other info. - This small species is mainly found in the lower 1/2 of Missouri. The white flowers only last for one day and are frequented by bees from the family Halictidae. Flowering is triggered by specific weather conditions, and populations of plants in a common area will commonly all flower on the same day.

The genus and species name for the plant both mean "bearing three" because the plant typically has three flowers present at once.

Photographs taken at the Sunklands Conservation Area, Shannon County, MO., 7-28-04 (DETenaglia); also at Babler State Park, St. Louis County, MO, 9-10-2018 (SRTurner).