Protologue Description:
Trachymene cyanantha differs from T glaucifolia (F. Muell.) Benth, and T. ochracea especially by having dimorphic papillae on the solitary mericarp: it has a chromosome complement of 2n=22.

Trachymene cyanantha D. E. Boyland; species nova T. ochraceae L. Johnson et T. glaucifoliae (F. Muell.) Benth. affinis ab hac umbellis mericarpiisque minoribus ab illa floribus caeruleis mericarpüs majoribus, mericarpio unico evoluto ab ambabus papillis in margine mericarpü majóribus obtusis papillas multo minores circumdantibus differt. Typus: prope Cheepie in Queensland, Pedley, 2449 (holotypus BRL103874). Isotypi distribuendi-K, CANB, NSW, AD, PERTH, L, US, AAU, B; US, GH, PNH.

Herba annua (vel biennis?). Caules glabri, solitarü vel pauci, simplices vel aliquando ramosi, humifusi usque erecti usque ad 45 cm altos raro prostrati. Folia petiolata; laminae glabrae raro pilos paucos dissitos instructi, ambitu depresse ovatae raro late ovatae, tripartitae. Folia basalia petiolis ,racilibus usque ad 11 cm longis plerumque pilos paucos basim versus instructi: laminae usque ad :m longae, plerumque 7 cm raro 10 cm latae; segmenta primaria anguste obtrullata usque late otrullata interdum trullata usque ad 5 cm longa usque ad 3 cm lata, irregulariter pinnatifida 1-4 segmentis secundariis anguste oblongis: segmenta secundaria integra vel irregulariter 2-3-lobata lobis usque ad 4 mm latis. Folia caulina inferiores praeter laminas minus divisas foliis basalibus similia; folia caulina superiores segmentis primariis anguste oblongis integris vel I-2-lobatis. Pedunculi glabri. Umbellae ± 5 usque ad 45, 10-16 mm diam., ± 25-40-flores. Bracteae glabrae, lineares acutae usque ad 4 mm longae. Pedicelli sub anthesi 2.4-3.6 sub fructu 3-5 mm longi. Sepala inconspicua. Petala caerulea late elliptica I-1.4 mm longa, 0.8-1.2 mm lata. Filamenta 1.2-1.8 mm longa. Antherae ± 0.5 mm longae. Styli 0.8-1.2 mm longi. Mericarpia solitaria ochracea, oblique rotundata ± 2.6-3.6 mm longa, ± 2-2.6 mm lata, papillosa; papillae dimorphae eae marginis 14-22 obtusae ± 0.5-0.7 mm longae ± 0.2 mm latae papillas 5-17 multo minores circumdantes. Chromosomatum numerus: 2n = 22.

Annual (perhaps biennial?) herb. Stems glabrous, solitary to several, unbranched or occasionally branched, procumbent to erect up to 45 cm high rarely prostrate. Leaves petiolate; blades glabrous or rarely with a few scattered hairs, depressed ovate or rarely broadly ovate in outline, tripartite. Basal leaves with petioles up to 11 cm long usually with a few hairs towards the base; blades up to 5 cm long up to 7 cm wide rarely 10 cm wide; primary segments narrowly obtrullate to broadly obtrullate sometimes trullate up to 5 cm long and up to 3 cm wide, irregularly pinnatifid with 1-4 narrowly oblong secondary segments; secondary segments up to 4 mm wide entire or with 2-3 unequal lobes. Lower cauline leaves similar to basal leaves but blade usually less dissected; upper cauline leaves with primary segments narrowly oblong, entire or 1-2-lobed. Peduncles glabrous. Umbels ± 5 to 45 per plant, 10-16 mm diam., ± 20-45-flowered. Bracts glabrous, linear acute up to 4 mm long. Pedicels in flower 2-4-3-6 mm long in fruit 3-5 mm long. Sepals inconspicuous. Petals blue, varying from very pale blue to deep blue, broadly elliptic, 1-1.4 mm long, 0.8-1.2 mm wide. Filaments 1.2-1.8 mm long. Anthers 0.5 mm long. Style 0.8-1.2 mm long. One mericarp only developed, yellow-brown, obliquely rounded, ± 2.6-3.6 mm long ± 2-2.6 mm wide, papillose. Papillae dimorphic, 14-22 obtuse marginal papillae ± 0.5-0.7 mm long ± 0.2-0.3 mm wide surrounding 5-17 much smaller papillae. Chromosome number: 2n = 22.

QUEENSLAND.-GREGORY SOUTH DISTRICT: 80 miles W of Quilpie towards Windorah, 4-9-1963, Cockburn 11 (pale blue flowers). MITCHELL DISTRICT: Barcarolle on the Thomson River, in 1929, Berney 92 (blue flowers). WARREGO DISTRICT: " Ambathalla ", May 1914. Barlow; Adavale Road. 28-8-1923, MacGillivray; about 20 miles E. of Quilpie, 9-7-1969, Anson 1; 57 miles from Charleville on Quilpie Road, red-brown gravelly fine sandy loam with mulga, I-9-1963, Everist 7517 (herb with central root and many branched prostrate stems, leaves dull green, flowers very pale blue): " Bardo ", Adavale. 5-4-1966, Anson (blue-flowered); 82 miles WNW. of Charleville. on road to Adavale, June 1967, Gittins 1224 (flowers blue, foliage not notably glaucous); 26°- 52' S., 145° 08' E., 15 miles S. of Cheepie, on hard red-brown loam with scattered Acacia aneura and Eucalvptus populnea, 9-9-1967, Pedley 2449 (herb to 18 inches, flowering stems arising from rosette of leaves, corolla pale blue fading to white); 8 miles S. of Quilpie on road to Toompine on mulga gravels, 28-9-1968, Williams 117 (blue-flowered, 12 inches high); 22.1 miles N. of Toompine on the old road on red mulga loams, 17-6-1969, Trapnell E42 (blue-flowered, 12-15 inches high); between Beechal Creek and 30 miles SW. of Charleville on Quilpie Road, Aug. 1969. Silcock; 26° 53' S., 144° 45' E., about 25 miles SW. of Cheepie, slightly undulating plain on sandy red loams over clay with scattered Acacia spp. and Eucalvptus terminalis, 17-11-1970, Boyland 854 (semi-erect herb, 22 cm high, flowers very pale blue, fruits yellow-brown).