Citation: R. Br., Prod. Fl. Nov. Holl. 317 (1910).

Derivation: Greek prason, a leek; phyllon, a leaf.

Synonymy: Not Applicable

Common name: None

Description:
Terrestrial glabrous herbs from diminutive to large, with ovoid or globular tubers, new tuber produced distant from that of the previous year; leaf solitary, lamina terete, hollow.

Flowers not resupinate, several or numerous in a raceme, from diminutive to moderate-sized, sometimes fragrant; bracts smaller than the ovary; perianth usually inconspicuous, commonly greenish, white or purple; dorsal sepal lanceolate or broad and acute, concave, sometimes erect and arched over the column, more frequently recurved; lateral sepals narrower, connate to free; petals usually shorter, lanceolate or linear; labellum above the column, sessile or on a movable well-developed claw attached to the base of the column, more or less trullate, undivided, usually erect and concave towards the base, recurved distally; margins crisped, ciliate, denticulate or entire; calli on the labellum simple and more or less longitudinal; column short below the anther; its margins produced into wings in the form of 2 free lateral processes, usually adnate to the basal margins of the stigmatic-plate (a vertical plate in front of the anther, consisting of a basal portion or an expanded style, and an upper portion bearing the stigma and the rostellum); rostellum prominent, becoming detached, with a thread-like stipe to which pollen masses adhere; pollinia 2, 2-lobed in each cell, pollen in many small oblong masses; stigma disc-shaped.

Distribution:  80-90 species, the majority temperate Australian; 4 in New Zealand and New Caledonia. Leek-orchids (spring-flowering), midge-orchids (autumn-flowering).

Biology: The autumn-flowering species with the labellum on a movable claw are pollinated by tiny flies, the spring- and summer-flowering species with a non-movable labellum are pollinated principally by nectar- seeking insects, mainly wasps.

Key to Species:

1. Column stem elongated; labellum on a movable claw; leaf clasping the stem for most of its length (autumn-flowering plants, section Micranthum)
2. Petals ciliate	P. morrisii 10.
2. Petals not ciliate
3. Labellum ciliate	P. archeri 1.
3. Labellum not ciliate
4. Labellum lanceolate, tapering into a long acute point	P. despectans 3.
4. Labellum obovate, acute or subacute
5. Petals greenish; labellum margin entire with a subacute apex; column appendage posterior lobe acuminate; anther mucro short, less than 0.1 mm long	P. nigricans 11.
5. Petals reddish; labellum margins serrate toward an acute apex; column appendage posterior lobe rounded; anther mucro long, c. 0.3 mm, bristle-like	P. rufum 14.
1. Column stem condensed; labellum not on a movable claw; leaf clasping basally, free for at least one-third of its length (spring- flowering plants, section Prasophyllum)
6. Ovary appressed to the stem, long, slender and flattened dorsiventrally
7. Labellum acutely reflexed about the middle, conspicuously white, base gibbous	P. australe 2.
7. Labellum slightly recurred from about the middle, the base not gibbous	P. elatum 4.
6. Ovary standing out from the stem, more or less turgid
8. Flowers not expanding, the floral segments very dark and parchment-like	P. goldsackii 7.
8. Flowers freely expanding, the floral segments green to reddish
9. Labellum callus with some pubescence
10. Flowers wholly greenish; lateral sepals 2-dentate; normally a tooth-like spur at the base of the column	P. pallidum 12.
10. Flowers with some purple or reddish tints; lateral sepals not 2-dentate; no tooth-like spur at the base of the column	P. fitzgeraldii 5.
9. Labellum callus without pubescence
11. Flowers less than 5 mm diam., segments to 2 mm long; column appendages absent or vestigial	P. macrostachyum 9.
11. Flowers more than 6 mm diam., segments more than 2.5 mm long; column with distinct appendages
12. Labellum usually with a lateral constriction near the tip; callus plate extending beyond the bend almost to the tip (narrow but much raised)	P. fuscum 6.
12. Labellum without a lateral constriction near the tip; callus plate hardly exceeding the bend, never reaching the tip (broad and not much raised)
13. Lateral sepals longer than the labellum; labellum base orbicular, broad, margins much incurved; callus plate with thickened glandular margins	P. hartii 8.
13. Lateral sepals shorter than the labellum; labellum base ovate, without markedly incurved margins; callus plate without thickened margins	P. patens 13.

Author: Not yet available