Thelymitra antennifera

Thelymitra antennifera is a tuberous, perennial herb, 10–25 cm tall with yellow flowers from July to October.[2] Its leaf is circular in cross–section, 5 to 12 cm long and 2 to 3 mm wide. The inflorescence consists of one to four yellow flowers on a wiry, zig-zagged often pinkish stem. Each flower is 20 to 40 mm across with a lemon or vanilla scent. The sepals and petals are 12 to 20 mm long and 4 to 6 mm wide, the sepals having a broad, reddish–brown band on their outer surface. The column is 5 to 6 mm long and 2 to 3 mm wide with dark brown arms that are ear-like and held high above the column.[3] As with others in the genus, it reproduces by seeds but is unusual in that it is one of the few that develops tubers on the end of stolon-like roots, allowing it to form new colonies.[4] The flowers are insect pollinated and open readily, even on cool days and are long-lasting.[5]

The species occurs in the South–West and Eremaean botanical provinces of Western Australia. It is also found South Australia and Victoria. In Tasmania it only occurs in a few small areas and is classified as an endangered species in that state.[3] Elsewhere it is widespread and common, growing in many habitats, especially shrub, heath and mallee. It sometimes forms dense, extensive colonies, flowering freely, especially after fire.[5]

The species was first described by John Lindley in 1840 in his A Sketch of the Vegetation of the Swan River Colony (1840) as Macdonaldia antennifera.[6] but was later renamed Thelymitra antennifera by the English botanist Joseph Dalton Hooker in The botany of the Antarctic voyage of H.M. discovery ships Erebus and Terror. III. Flora Tasmaniae[7] The specific epithet (antennifera) is from the Latin antenna, (classically "a sail yard"), and -fer meaning "-bearing", referring to the lateral appendages on the column.[8][9] The genus name Macdonaldia, honours "Mrs. Smith, née Macdonald, a lady who has examined the Orchidaceous plants of that island with great care, and from whom a most beautiful series of dried specimens has reached me through the offices of Mr. Gunn".[10]

Five hybrids are recognised–

• Thelymitra antennifera (Lindl.) Hook.f. x Thelymitra gregaria D.L.Jones & M.A.Clem.[11]
• Thelymitra antennifera (Lindl.) Hook.f. x Thelymitra luteocilium Fitzg.[12]
• Thelymitra antennifera (Lindl.) Hook.f. x Thelymitra macrophylla Lindl. crimson sun orchid[13]
• Thelymitra antennifera (Lindl.) Hook.f. x Thelymitra maculata Jeanes western wheatbelt sun orchid[14]
• Thelymitra antennifera (Lindl.) Hook.f. x Thelymitra vulgaris Jeanes scarce sun orchid[15]

Thelymitra species are readily cultivated in pots.[16]