757. CHLORANTHUS OLDHAMII Chloranthaceae. James Cullen

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1 757. CHLORANTHUS OLDHAMII Chloranthaceae James Cullen Summary. Chloranthus oldhamii Solms-Laub. is described, and its position in the family Chloranthaceae is discussed. It is illustrated with a painting and line drawing. Suggestions for its successful cultivation are given. The Chloranthaceae is a small, and to gardeners rather obscure, family of herbs, small shrubs and trees (four genera and about 75 species) distributed through tropical Asia, America and Madagascar with extensions into adjacent subtropical areas (especially SE Asia and New Zealand). In spite of its small size, it is, and has been for some time, of considerable interest to botanists and phylogenists, following the report (Thompson & Bailey, 1916) that the xylem of one of the genera (Sarcandra) was made up entirely of tracheids (as in the gymnosperms), with no vessels present. This was considered to be a very primitive character in the angiosperms and focused interest on the family as possibly being an early-evolved branch of the Angiosperm stock. The occurrence of many Cretaceous fossils clearly belonging to the family (see, for example, Crane et al., 1989; Ecklund et al., 1997) reinforced this view. In spite of the fact that Carlquist (1987) showed that Thompson and Bailey s observations were not entirely correct, vessels being found in the secondary xylem in the roots (though not in the stems) of various species of Sarcandra, the family has continued to be of interest to phylogenists. In the latest APG classification (APG, 2009), the family is to be found in a basal position near the Magnoliales, and Zhang et al. (2011) report that Chloranthaceae...is one of the earliest diverging angiosperm families.... Interest in the family continues and much research on the family is going on in various parts of the world. Chloranthus Swartz is a genus of about 18 species from south-east Asia (mainly China, where there are 12 species). Chloranthus and Sarcandra Gardner are distinguished from the other genera (Ascarina Forst. and Hedyosmum Sw.) by their herbaceous habit and generally bisexual flowers. In Sarcandra each flower has only a single stamen, whereas in Chloranthus there are usually three apparent stamens in each flower (seedetails below). C. oldhamii is easily distinguished from Curtis s Botanical Magazine 2013 vol. 30 (2): pp The Board of Trustees of the Royal Botanic Gardens, Kew 2013.

2 Plate 757 Chloranthus oldhamii georita harriott

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4 the rest of the 12 species of the genus in China by its herbaceous habit and the presence of a short but distinct style. In spite of all this interest in the botanical features of the family, it has made little impact in horticulture in fact, this is only the second appearance of the family in the pages of this magazine Chloranthus monostachyos R. Brown, which is now generally considered to be a synonym of C. serratus (Thunberg) Roemer & Schultes was described from a plant of the latter collected late in the season (see Kong et al., 2002) and appears as plate 2190 of volume 48, published in The plants tend to be herbs or small shrubs of no particular distinction, and the flowers are small and without petals, hence of little value to gardeners. However, in the last 15 years, the plant which forms the subject of the present plate has become available and is now quite widely grown for the sake of its evergreen leaves and spikes of flowers which, though without petals, are conspicuous because of their white swollen connectives and anthers. The plant illustrated was introduced to cultivation by Mr Bleddyn Wynn-Jones of Crûg Farm Plants in North Wales (Crûg Farm Plants, Griffiths Crossing, Caernarfon, Gwynedd LL55 1TU). He collected it in Taiwan in December of 1992 (Taiwan, Dahlung-Dahli, just north of Hualien, collected from the edge of moist forests in shade on steep banks from the edge of the trail, ca 1000 m, BSWJ 2019). Mr Wynn-Jones grew the plant on and eventually offered it for sale. In 2001, material was acquired from Crûg Farm by Dr P. F. Yeo of the Cambridge University Botanic Garden. Because of uncertainties as to its hardiness, the plant was tried in various locations, both out-of-doors and under glass. The only planting to have survived in Cambridge until now is that in the eastern wing of the tropical house, where it provides a dense evergreen ground-cover, flowering from December to March, in a shady, moist situation; it spreads there extensively both by rhizomes and by seed, but is relatively easy to control. The illustrations and description in this article are taken from this plant. However, Mr Wynn-Jones tells me that he and others grow the plant in the open, where it dies down in the winter and scarcely spreads (seed is apparently not produced). It also seems that most of the inflorescences in the glasshouse material are bisexual (these are the attractive elements of the plant), and a few are female, whereas in material grown out-of-doors the inflorescences tend to be more The Board of Trustees of the Royal Botanic Gardens, Kew

5 mixed, with female flowers towards the base. Further observations are required on this point. The early history of this species is of some interest, as it involves the unfortunate Richard Oldham ( ) after whom it is named, who discovered it Taiwan in 1863; it was described by Solms-Laubach in De Candolle s Prodromus in The type-material came from Tanshin under Oldham s collection number 466. Oldham was the last professional collector to be sent out from Kew in the 1860s, when he was in his early twenties. His main collecting areas were China and Japan, but he suffered many delays while waiting for ships to carry him from one place to another, and he used one of these for his first visit to Taiwan in He seems to have had some personal difficulties with Sir William Hooker, who was then Director of the Royal Botanic Gardens: Hooker seemed to think that Oldham was both lazy and incompetent in the handling of money this in spite of the fact that he introduced over 80 species new to science to the garden and collected specimens for the herbarium. Hooker terminated his contract in 1863 and Oldham remained in the Far East, as a self-employed collector, again visiting Taiwan in Unfortunately he died there in November 1864, aged 26. Further details of his short life are available in Coats (1969) and on a recent blog from Kew ( Chloranthus oldhamii shows many morphological features of interest. Its flowering stems are upright, and bear two pairs of opposite leaves very close together, so that the leaves superficially appear as single whorls of four at the top of the unbranched stems. These leaves are evergreen in plants grown in the glasshouse, apparently deciduous in those grown out-of-doors, and are toothed towards the apex. They bear interpetiolar stipules (like those of many Rubiaceae), which are narrow, and irregularly toothed. The short petioles are attached to stems which are rather flattened, and with two channels on each flat surface. The inflorescences are borne in the centre of the pseudowhorl of leaves and are secund spikes. The bisexual flowers are zygomorphic, each subtended by a bract, and with the three stamens borne on a small ledge or projection about half-way up the ovary on one side; the filaments are short and the connectives are much longer, finger-like, fleshy and white; the central one bears two pollen sacs, the 72 The Board of Trustees of the Royal Botanic Gardens, Kew 2013.

6 Fig. 1. Chloranthus oldhamii. A, part of inflorescence, 4.5; B, section of fruit, 9; C, section of stem at leaf base, 9; D, bisexual flower, showing central stamen with two anthers and lateral stamens with one anther, and bag-like connectives, 7.5. Drawn by Georita Harriott from plants grown at Cambridge University Botanic Garden. lateral ones one pollen sac each, meaning that there are 1 / / 2 stamens in each flower (this is reminiscent of the Fumariaceae, in which there are two ensembles of stamens arranged in this way). The female flowers are also slightly zygomorphic in that they bear a ledge equivalent to that which supports the stamens in the bisexual flowers. Because the stamens are borne about half-way up the ovary in bisexual flowers, the ovary is considered to be half-inferior; this is more difficult to tell in purely female flowers, as the ledge is not conspicuous (Fig. 1). Cultivation. All in all, this is an interesting and easily-grown plant for a moist, shaded place in the garden, whether in the open or in the glasshouse. Its botanical interest makes it a talking point among The Board of Trustees of the Royal Botanic Gardens, Kew

7 certain groups, and the spikes of flowers produced copiously in the late winter and spring are attractive and sweetly scented. Propagation is by seed or by division of the rhizomes. Chloranthus oldhamii Solms-Laubach in De Candolle,Prodromus 16(1): 476 (1869). Type: (Taiwan), Tanshin, Oldham 466 (G-DC, K). Chloranthus serratus misapplied, not C. serratus (Thunberg) Roemer & Schultes. Description. Clump-forming, evergreen, slightly woody herb with brownish, horizontal creeping rhizomes and vertical, whitish, somewhat fleshy roots, spreading rapidly by extension of the rhizomes and ultimately by seed. Stems arising form the rhizomes, unbranched, to 50 cm, reddish brown below, paler greenish brown above, glabrous, bearing two to three distant nodes from which opposite leaves have fallen and, at the top, an apparent whorl of four leaves actually two pairs of opposite leaves with almost no internode between them. Upper part of stem flattened laterally. Stipules minute, pointed, toothed, soon falling. Leaves with petioles 1 2cm, often reddish brown; blades chartaceous, obovate to very broadly obovate, cm, shining and dark green above, paler beneath, glabrous above, minutely papillose-hairy along the veins beneath, somewhat puckered. Main lateral veins about seven to eight pairs curving, joined by a close network of smaller veins. Margins toothed with forwardly pointing teeth; apex acuminate. Inflorescences stalked in the axils of the four terminal leaves, bisexual and female or occasionally mixed, female below, bisexual above. Bisexual inflorescences with peduncles to 5 cm, reddish; flowers in somewhat secund spikes, two to three together, arising from the top of the peduncle, pendulous and somewhat crozier-like when young, erect-spreading when mature. Perianth absent; ovary with a bract at its base, bag-like in flower, bearing the stamens; stigma 1, borne on a short but distinct style, fringed; ovule 1, apical, pendulous; stamens 3,borneona small swelling or ledge about half-way up the ovary on one side, the flowers thus zygomorphic, and half-epigynous, the margins of this swelling brownish, bract-like and occasionally two-toothed. Stamens 3, filaments very short, connectives conspicuous, white, banana- or finger-shaped, bluntly pointed at the apex, ca 5 mm; the central anther bears two anther-sacs on its inner surface, the other two each bear a single anther-sac. Fruit a pear-shaped drupe, to 3 mm, brownish. Purely female inflorescences are borne similarly, but are forked or widely branched and without the conspicuous anthers; each ovary has a small swelling on the side equivalent to that which bears the stamens in bisexual flowers, but this is smaller; the bract to the ovary is cup-like with fringed brownish margins. Seed more or less spherical, ca 2 mm in diameter, brownish. Distribution. Taiwan. In woods and shaded banks. Flowering time. Winter to early spring in glasshouses, later out-ofdoors. Acknowledgements. I am grateful to Mr George Sherriffs of the library at the Royal Botanic Garden, Edinburgh for assistance in finding some of the references. 74 The Board of Trustees of the Royal Botanic Gardens, Kew 2013.

8 REFERENCES APG III (2009). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society 161: Carlquist, S. (1987). Presence of vessels in wood of Sarcandra (Chloranthaceae); comments on vessel origins in Angiosperms. American Journal of Botany 74(12): Coats, A. (1969). The Quest for Plants. Studio Vista, London. Crane, P.R., Friis, E.M. & Pedersen, K.R. (1989). Reproductive structure and function in Cretaceous Chloranthaceae. Plant Systematics & Evolution 165: De Candolle, A.P. (1879). Prodromus Systematis naturalis Regni vegetabilis, Vol. 16. V. Masson, Paris. Ecklund, H., Friis, E.M. & Pedersen, K.R. (1997). Chloranthaceous floral structures from the late Cretaceous of Sweden. Plant Systematics & Evolution 207: Kong, H.-Z., Chen, Z.-D. & Liu, A.M. (2002). Phylogeny of Chloranthus (Chloranthaceae) based on nuclear ribosomal ITS and plastid TRN-LF frequency data. American Journal of Botany 89(6): Thompson, W.P. & Bailey, I.W. (1916). Are Tetracentron, Trochodendron and Drimys specialised or primitive types? Memoirs of the New York Botanical Garden 6: Zhang, Q., Antonelli, A., Field, T.S. & Kong, H.-Z. (2011). Revising taxonomy, morphological evolution and fossil calibration strategies in Chloranthaceae. Journal of Systematics and Evolution 49: The Board of Trustees of the Royal Botanic Gardens, Kew