Aralia L.
Aralia is a genus of ca. 40-55 species, mainly distributed in SE-Asia (primarily China) and a few in the Americas. Several species are economically important: ten species are cultivated as ornamentals in Europe (Frodin 1997) and others are used medicinally or as a vegetable.
The taxonomy of Aralia is still very controversial and recent treatments by Asian taxonomists are in disaccord (compare for instance Wen 2004 and Xiang & Lowry 2007). Species delimitation and even the generic limits are unclear and, unfortunately, the circumscription of some of the cultivated taxa (especially those related to Aralia elata) remains critical. As a consequence the present treatment of the Aralia elata-group might be merely provisional. Two distinct sections are represented in cultivation (and as escapes): section Dimorphanthus (Miquel) Miquel with prickly trees or shrubs (Wen 2004) and section Aralia with unarmed perennial herbs (Wen 2011).
Species of Aralia are often strongly rhizomatous and intensive clonal reproduction may sometimes occur (although usually less so than, for instance, in Rhus) (see also Adolphi 1995, Berg & al. 2009).
1. Spiny shrub to small tree === 2. Aralia elata
1. Unarmed herb or shrub === 2
2. Inflorescence umbels with up to 40 or more flowers. Pedicels up to 12 mm long. Fruit black === 1. A. cordata
2. Inflorescence umbels with (7-) 10-25 flowers. Pedicels up to 8 mm long. Fruit brownish purple === 3. A. racemosa
Literature
Adolphi K. (1995) Neophytische Kultur- und Anbaupflanzen als Kulturflüchtlinge des Rheinlandes. Nardus 2: 272 p.
Berg C., Heber G. & Drescher A. (2009) Aralia elata (Miq.) Seem. – eine neue invasive Art? Mitt. Naturw. Ver. Steiermark 139: 135-147.
Frodin D.G. (1997) Aralia. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 370-372.
Jonsell B. & Jonsell L. (2010) Aralia. In: Jonsell B. & Karlsson T. (eds.), Flora Nordica, vol. 6. The Bergius Foundation, Stockholm: 163.
Stace C. (2010) New flora of the British Isles, 3th ed.: XXXII + 1232 p. Cambridge University Press.
Wen J. (1993) Generic delimitation of Aralia (Araliaceae). Brittonia 45: 47-55.
Wen J., Shi S., Jansen R.K. & Zimmer E.A. (1998) Phylogeny and biogeography of Aralia sect. Aralia (Araliaceae). Am. J. Bot. 85(6): 866-875.
Wen J. (2004) Systematics and biogeography of Aralia L. Dimorphanthus (Miq.) Miq. (Araliaceae). Cathaya 15-16: 1-187.
Wen J. (2011) Systematics and biogeography of Aralia L. (Araliaceae): revision of sections Aralia, Humiles, Nanae, and Sciadodendron. Contr. U.S. Nat. Herb. 57: 1-172.
Xiang Q. & Lowry P.P. (2007) Araliaceae. In: Wu Z.Y. & al. (eds.), Flora of China, vol. 5. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis: 435-491.