Crocosmia crocosmiiflora (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Crocosmia crocosmiiflora (Lemoine ex E. Morren) N.E.Br.

Protologue: Trans. Roy. Soc. S. Africa 20: 264 (“ crocosmiaeflora ”“, 1932).

Family: Iridaceae

Chromosome number: 2n= 22

Montbretia ×crocosmiiflora Lemoine ex E. Morren (1881), Tritonia crocosmiiflora G. Nicholson (1887).

• Garden montbretia, autumn gold (En)
• Papua New Guinea: etaetava (Central Province)
• Vietnam: nghệ hương.

C. ×crocosmiiflora developed as a hybrid between C. aurea (Pappe ex Hook.) Planchon and C. pottsii (M’Nab ex Baker) N.E.Br. in 1880 in France and became a popular garden plant. In South-East Asia it is also frequently cultivated as an ornamental, usually in mountainous regions, e.g. in Java. Escapes from gardens occur worldwide, also in South-East Asia, e.g. in Peninsular Malaysia, Sumatra, Flores and New Guinea.

In Papua New Guinea crushed leaves are inhaled to free the nasal passage when blocked due to a head cold. In East Africa leaf-sap and a decoction of the corms are drunk to treat malaria and arthritic rheumatism. C. ×crocosmiiflora is an important garden ornamental, and cultivated globally for this purpose. The flowers yield a yellow dye, which is sometimes used as a substitute for saffron ( Crocus sativus L.).

The naphthazarin derivatives tricrozarin A and B have been isolated from C. ×crocosmiiflora corms. Tricrozarin A showed antimicrobial activity against gram-positive bacteria, fungi and yeasts, and tricrozarin B displayed marked antitumour activity against HeLa S3 cells in vitro.

A series of acylated saponins, masonosides A-C, have been isolated from corms of C. masonorum (L. Bolus) N.E.Br., together with two desacylmasonosides and desacylcrocosmioside A.

A herb up to 50(-125) cm tall, with depressed-globose to ovoid corms 1.5-2.5 cm in diameter, having brown membranous tunics, often in groups of 2-3 or connected by slender stolons. Leaves basal and cauline, distichously alternate, simple, basal leaves linear-lanceolate to ensiform, 30-75 cm × 1-2.5 cm, acute, veins numerous and parallel, middle vein prominent, cauline leaves few, smaller than basal ones, sheathing at base. Inflorescence a large, laxly branched panicle, slightly zigzag branched; peduncle 25-50(-125) cm long, 2-3-ribbed; bracts up to 1 cm long, reddish. Flowers bisexual, slightly zygomorphic, 3-merous; perianth funnel shaped, tube 1-1.5 cm long, slightly curved, with 6 widely spreading lanceolate to oblong segments 1.5-2.5 cm long in 2 whorls, orange or reddish-orange, often red-blotched; stamens 3, inserted near the mouth of the perianth tube opposite the outer tepals, widely exserted; ovary inferior, 3-celled, style 3-3.5 cm long, 3-branched at apex, branches often shortly forked. Fruit an ellipsoid-obovoid, deeply 3-lobed capsule up to 7 mm × 9 mm, usually without viable seeds.

C. ×crocosmiiflora rarely sets seed and spreads mainly by its stolons and corms.

Crocosmia comprises 9 species and is restricted to southern Africa and Madagascar. It is closely related to Tritonia and Chasmanthe . C. ×crocosmiiflora has characters intermediate between its two parent species ( C. aurea and C. pottsii ). However, sometimes cultivated plants closely resemble one of the parents, although they may also differ considerably from both. It would be better to consider C. ×crocosmiiflora as a cultivar group.

C. ×crocosmiiflora prefers damp habitats. In Malesia it can be found as a garden escape in open forest, moist grassland, roadsides and on waste ground, at 250-3500 m altitude, and it can be locally abundant. Under favourable conditions it may form large clumps. It is hardy to frost, and can stand temperatures as low as -15°C. C. ×crocosmiiflora is grown in well-drained but moisture-retentive soils enriched with organic matter.

Management C. ×crocosmiiflora can be propagated by division of established clumps, but sporadically also by seed sown fresh into a loam-based propagating mix with additional sharp grit.

C. ×crocosmiiflora is commonly cultivated in many regions of the world. The genetic diversity of these cultivated plants is unknown, but it is a variable hybrid forming the basis for a wide range of selections. In southern Africa 3 species, amongst which the parents of C. ×crocosmiiflora , have a wide distribution range, but the others are local endemics.

C. ×crocosmiiflora will remain important as an ornamental. Its possible applications as a medicinal plant merit further research because it has shown interesting pharmacological properties, e.g. antimicrobial and antitumour activities, and it is easy to cultivate.

347, 601, 602, 962.

120, 204.

• '

R.P. Escobin