Bupleurum L.
Bupleurum is a genus of ca. 180-190 species, predominantly native to Eurasia, North Africa and Macaronesia. Three species are usually claimed as natives in Belgium: Bupleurum falcatum L., B. rotundifolium L. and B. tenuissimum L. (Lambinon & Verloove 2012). In fact, Bupleurum rotundifolium is at most an archaeophyte of arable land and is extinct as such since the 1950’s. It now sometimes occurs as ephemeral alien (escape from cultivation, grain alien, etc.). Bupleurum tenuissimum was long presumed extinct; it was last seen in 1928 in Nieuwpoort but was recently rediscovered in Knokke-Heist in nature reserve Zwin (see: http://waarnemingen.be/soort/view/2378).
Molecular data strongly support the monophyly of Bupleurum (e.g. Neves & Watson 2004, Wang & al. 2008). Leaf venation (pinnately veined vs. parallel veined) appears to be an important feature for the infrageneric classification of the genus (Neves & Watson l.c.).
1 Upper leaves perfoliate. Bracts absent === 2
Upper leaves not perfoliate. Bracts present === 4
2 Cauline leaves ovate-lanceolate. Ovary and fruit tuberculate. Rays 2-3(-4) === Bupleurum subovatum
Cauline leaves ovate to (sub-) orbicular. Ovary and fruit smooth. Rays usually 5-10 === 3
3 Leaves glaucous. Rays (3-)5(-10), raylets subequal (native) === B. rotundifolium
Leaves yellowish-green. Rays 7-10, central raylets reduced === B. croceum
4 Perennial === 5
Annual === 6
5 Evergreen shrub, stem woody below. Leaves pinnately veined with a strong midrib and many lateral veins. Fruit 4-12 mm long. Bracts 5-8, oblong to obovate === B. fruticosum
Stem entirely herbaceous. Leaves parallel veined. Fruit 2-4 mm long. Bracts 1-4(-5), linear (native) === B. falcatum
6 Most umbels with at least 4 rays. Fruit longer than wide, more or less smooth === B. gerardi
Most umbels with 2-3 rays. Fruit as long as wide, tuberculate (native) === B. tenuissimum
Additional aliens: Bupleurum odontites L. (syn.: B. fontanesii Guss. ex Caruel) (E-Medit., vector unknown) and B. praealtum L. (syn.: B. junceum L.) (S and C-Eur., W-As., vector unknown).
Literature:
Briquet J.I. (1897) Monographie des Bupleures des Alpes maritimes: 131 p.
Cauwet-Marc A.-M. (1976) Biosystématique des espèces vivaces de Bupleurum L. (Umbelliferae) du bassin Méditerranéen occidental. Université des Sciences et Techniques du Languedoc Perpignan, 3 vol., 848 p.
Fabri R. (1987) Les Bupleurum adventices de Belgique et du Grand-Duché de Luxembourg. Dumortiera 37: 2-6.
Fabri R. (1993) Umbelliferae. In: Flore Générale de Belgique, vol. 5, fasc. 2. Jardin Botanique de l’Etat, Bruxelles: 105-360.
Krasnoborov I.M. (1998) On Northern Asian and North American species of Bupleurum (Umbelliferae). Bot. Zhurn. 83(2): 120-127.
Lambinon J. & Verloove F. (avec coll. Delvosalle L., Toussaint B., Geerinck D., Hoste I., Van Rossum F., Cornier B., Schumacker R., Vanderpoorten A. & Vannerom H.) (2012) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Sixième édition. Jardin botanique national de Belgique, Meise: CXXXIX + 1195 p.
Neves S. (2003) Bupleurum. In: Nieto Feliner G. & al. (eds.), Flora Iberica, vol. 10. Real Jardín Botánico, Madrid: 240-265.
Neves S.S. & Watson M.F. (2004) Phylogenetic Relationships in Bupleurum (Apiaceae) Based on Nuclear Ribosomal DNA ITS Sequence Data. Annals of Botany 93: 379-398. [available online at: http://aob.oxfordjournals.org/content/93/4/379.full.pdf]
Ostroumova T.A. & Kljuykov E.V. (2015) Fruit structure and microsculpture in the annual species of the genus Bupleurum, section Perfoliata (Umbelliferae). Phytologia Balcanica 21(2): 117-127. [available online at: http://www.bio.bas.bg/~phytolbalcan/PDF/21_2/PhB_21_2_03_Ostroumova_&_Kl... ]
Ozcan T. (2004) Analysis of the fruit surfaces in Bupleurum L. (Umbelliferae) with SEM. Pl. Syst. Evol. 247(1-2): 61-74.
Richardson J.E. (1997) Bupleurum. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 5. Cambridge University Press, Cambridge: 406-407.
Snogerup S. & Snogerup B. (2001) Bupleurum L. (Umbelliferae) in Europe – 1. The annuals, B. sect. Bupleurum and sect. Aristata. Willdenowia 31: 205-308. [available online at: http://www.ingentaconnect.com/content/bgbm/will/2001/00000031/00000002/art00001]
Šourková M. (1976) Rod Bupleurum L. v Ceskoslovensku. Zprávy Ceskoslov. Bot. Spolecn. Ceskoslov. Akad. Ved 1976(1): 1-16.
Tutin T.G. (1968) Bupleurum. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 2. Cambridge University Press, Cambridge: 345-350.
Wang C.-B., Ma X.-G. & He X.-J. (2011) A taxonomic re-assessment in the Chinese Bupleurum (Apiaceae): Insights from morphology, nuclear ribosomal internal transcribed spacer, and chloroplast (trnH-psbA, matK) sequences. Journal of Systematics and Evolution 49(6): 558–589.
Wang Q.Z., Song-Dong Z., Liu T.-Y., PangY.-L., Wu Y.-K. & He X.-J. (2008) Phylogeny and classification of Chinese Bupleurum based on nuclear ribosomal DNA internal transcribed spacer and rps16. Acta Biologica Cracoviensias Botanica 2: 105-116. [available online at: http://www2.ib.uj.edu.pl/abc/pdf/50_2/105-116-Wang.pdf ]
Wolff H. (1910) Bupleurum. In: Engler A. (ed.), Das Pflanzenreich 214 (IV/228). Engelmann, Leipzig: 36-173.