Microtis

Microtis, [my-krow-tiss] from mikros, small, and ous, otos, an ear; referring to the appearance of the anthers.

A genus commonly called “Mignonette Orchids” in Western Australia, and somewhat similar to Prasophyllum in habit, but easily distinguished from it by the smaller flowers numerous on a terminal spike, which are usually greenish and not reversed. The stigma is enclosed within a hood formed by the lateral appendages of the column.

Fertilisation is performed by insects, which, by touching the very small and sensitive rostellum, cause the pollen either to fall and adhere to the stigma, or be carried by them to aother flower. Like Prasophyllum, species are considered difficult to identify.

The genus Microtis extends to New Zealand and also to New Caledonia, Java, Formosa, Philippines, Japan and Southern China. Seven of the nine Australian species are endemic.

Microtis Species in Western Australia

Microtis alba, white.
Stems often above 1 ft. high. Leaf with a long sheath, the blade often exceeding the spike. Flowers numerous, much incurved, white, in a sometimes very dense spike. Lateral sepals rolled back. Upper sepal acuminate, contracted at the base. Lip broadly two-lobed, the margins wavy or fringed. Favours all varieties of soil.
W.A.: Albany, Cannington, Dumbleyung, Greenbushes, Harvey, Jarnadup, Jarrahdale, Mandurah, Pindalup, Stirling Range, York. October – December.

Microtis atrata, blackened, referring to the specimens drying black.
A minute species. Leaf short but with the long sheath reaching almost to the tiny flowers in a rather dense spike of 1/2 to 1 in., lateral sepals very blunt, not hidden, spreading, not recurved or revolute, upper sepal broad, lip broad, entire. Grows in wet places.
W.A.: Albany, Gosnells, Guildford, Kalamunda, Midland Junction, Pindalup,
South Australia, Tasmania, Victoria.

Microtis gymnadenoides, like Gymnadenia.
Stem slender with one basal scale, 10 to 18 in. high. Leaf rather long, the free part from 4 to 7 in. Spike rather long, narrow, cylindrical. Flowers white, upper sepal broad, ovate, concave, with a small point at the top; lateral sepals spreading, not recurved, rather blunt, much like the lateral petals, but a little broader. Lip crisped in the middle part, the disk marked by two small appendages, and bearing a small thickening towards the end. (Described Journal Proceedings Mueller Society, April, 1903). Note by Dr. Diels: “Collected close to Albany toward the north in wet, sandy flats. This species seems to be related to Microtis pulchella. It is different, however, from Bentham’s description, in the longer leaf, the dorsal sepal wider and more concave, the crisped margin of the labellum, and the larger flowers.”
W.A.: Albany district. November.

Microtis media, intermediate.
A tall species, leaf narrow, flowers white, much recurved, lip notched at tip, with two definite lateral basal callosities.
W.A.; Albany, Jarnadup, Pinjarra, York. September-December.

Microtis orbicularis, disk-shaped labellum
Stem rush-like, Lip to about 12 in., leaf sometimes longer, sometimes shorter than the spike. Spike, rising at a slight angle to the stem, not crowded and with a flatter appearance than in other species of the genus. Flowers, light green, minute, sessile. Dorsal sepal forms an obtuse hood over the column, lateral sepals about the same length or shorter than dorsal sepal, shorter than lip and hidden by it. Lateral petals very minute and spreading, points curving backwards. Lip broad and obtuse, projecting downwards. Column very small, with distinct linear auricles. Favours swampy ground.
W.A.: Bellevue, Cannington, Highbury, Pindalup. October.
South Australia.

Microtis parviflora, small-flowered.
A slender plant about 3 in. high. Leaf-lamina leek-like, usually much exceeding the inflorescence. Flowers green, on short stalks, smaller than those of Microtis porrifolia, commonly in a fairly dense spike, but the latter often attenuated. Lateral sepals recurved or revolute in the mature flower. Lip entire, with two well-defined callosities at base, none at tip.
WA.
All other Australian States.

Microtis porrifolia, leek-leaved,
- see Orchid Illustration 2, no 5
A tall, stout species over 1 ft. high, with a long leaf and dense spike of small greenish flowers, Lateral petals relatively wide, oblong-oval, much shorter than the recurved lateral sepals, upper sepal wide, concave. Lip with three callosities on the disk, notched at tip, the margin usually crisped.
W.A.: Albany, Darlington, Swan View. October.
All other Australian States.

Microtis pulchella, beautiful.
Stem slender, under 1 ft. Leaf narrow and short. Flower-spike not dense, rarely 2 in. long. Upper sepal blunt, not much broader than the spreading lateral sepals; petals incurved over column, same length but much narrower than lateral sepals.
W.A.: Swan View. September.

Microtis truncata, truncate, referring to shape of lip.
A plant of slender habit. Spike about 8 & 1/2in. long, bearing about 40 distant flowers. Flowers light-coloured, on short stalks, subtended by a small awl-like bract reaching a little above the base of the much twisted ovary. Petals linear-falcate, as long as lateral sepals, which are recurved or rolled back in mature flowers, upper sepal broad; lip truncate with three well-defined callosities, two at the base and one in the middle extending almost to the tip. (Described Transactions and Proceedings Royal Society S.A., XLIV., 1920.)
W.A.: – Albany, Greenbushes, Jarnadup. December.

West Australian Orchids Series

1. West Australian Orchids
2. Orchid Illustration 1 - Caladenia
3. Orchid Illustration 2
4. Orchid Illustration 3
5. West Australian Orchid Types
6. Naming and Classification of Orchids
7. Structure, Fertilization and Reproduction of Orchids
8. Collection of Orchids
9. Glossary of Orchid Terms
10. Caladenia
11. Diuris
12. Drakea
13. Eriochilus
14. Glossodia
15. Leptoceras
16. Lyperanthus
17. Microtis (This post)
18. Prasophyllum
19. Pterostylis
20. Thelymitra

Related posts:

1. Prasophyllum
2. Lyperanthus
3. Eriochilus
4. Diuris
5. Leptoceras

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