Campanula
Campanula L.
Campanula is a genus of ca. 300 species, all native to northern and temperate regions. Its largest species diversity occurs in the Mediterranean area and Turkey. Eight species are native in Belgium but only few are more or less widespread: Campanula cervicaria L., C. glomerata L., C. patula L., C. persicifolia L., C. rapunculoides L., C. rapunculus L., C. rotundifolia L. and C. trachelium L. Most of these are also cultivated as ornamentals (see also Eddie & Cann 2000) and only occur as garden escapes in large parts of Belgium.Campanula is popular among gardeners and several additional species are cultivated as ornamentals. The exact identity of some of these garden plants (especially the procumbent or long-trailing species from rock gardens) remains obscure and requires further study. Taxonomic boundaries between some related species might have become blurred as a result of selection and hybridisation.
1. Tiny, hispid annual, 3-10(-30) cm tall. Corolla 3-5 mm long === 2. Campanula erinus
1. Often taller, glabrous or hairy biennial or perennial. Corolla always much larger === 2
2. Calyx with five teeth alternating with five deflexed appendages === 6. C. medium
2. Calyx with five teeth, without appendages === 3
3. Flowers sessile in dense heads (native) === C. cervicaria and C. glomerata
3. Flowers on long or short pedicels, never in dense heads === 4
4. Capsule opening by apical or subapical pores === 5
4. Capsule opening by basal or median pores === 7
5. Lower leaves ovate-orbicular, cordate at base. Plant glabrous. Pores subapical === 1. C. carpatica
5. Lower leaves ovate-oblong to lanceolate-linear, not cordate at base. Plant hairy or glabrous. Pores apical === 6
6. Calyx-lobes lanceolate-ovate, with regularly serrate margins === 4. C. lactiflora
6. Calyx-lobes linear-lanceolate, entire or with some minute basal teeth (native) === C. patula, C. persicifolia and C. rapunculus
7. Calyx teeth linear to setaceous, less than 1 mm wide at base === 8
7. Calyx teeth lanceolate to ovate, at least 1 mm wide at base === 9
8. Mid stem leaves linear to linear-elliptic, tapered to base, nearly entire (native) === C. rotundifolia
8. Mid stem leaves ovate-oblong, rounded at base, serrate === 9. C. rhomboidalis
9. Stem erect, usually > 75 cm tall. Capsule pendent, opening by basal pores === 10
9. Stem procumbent to ascending, usually much shorter. Capsule erect, opening by median pores === 12
10. Calyx teeth patent to reflexed at anthesis (native) === C. rapunculoides
10. Calyx teeth erect to erecto-patent === 11
11. Cauline leaves sessile, rounded or cuneate at base. Stem not sharply angular, glabrescent to softly pubescent. Corolla 40-50 mm long === 5. C. latifolia
11. Cauline leaves petiolate, cordate at base. Stem sharply angular, hirsute hairy. Corolla 20-35 mm long (native) === C. trachelium
12. Corolla campanulate to funnel-shaped, lobed for 1/3-1/4. Style included in corolla. Leaves once serrate === 7. C. portenschlagiana
12. Corolla funnel-shaped to star-shapped, lobed for at least ½. Style shortly or distinctly exserted from corolla. Leaves double serrate === 13
13. Style distinctly exserted. Leaves ca. 25-30 mm across. Plant tufted, usually glabrous, rarely hairy. Corolla ca. 10-20 mm across. Calyx teeth up to 5 mm long === 3. C. fenestrellata
13. Style shortly exserted. Leaves 30-50(-70) mm across. Plant often with long trailing stems, usually hairy, rarely glabrous. Corolla ca. 20-40 mm across. Calyx teeth up to 12 mm long === 8. C. poscharskyana
Literature
Crook C. (1951) Campanulas. Their cultivation and classification. Country Live Ltd., London: 256 p.
Eddie W.M.M. & Cann D.C.G. (2000) Campanula. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 466-476.
Fedorov A.A. & Kovanda M. (1976) Campanula. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 4. Cambridge University Press, Cambridge: 74-93.
Hillegers H.P.M. & Weeda E.J. (2003) Klokjes op muren en rotsen in Limburg. Natuurh. Maandbl. 93: 61-70.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Lambinon J., Delvosalle L., Duvigneaud J. (avec coll. Geerinck D., Lebeau J., Schumacker R. & Vannerom H. (2004) Nouvelle Flore de la Belgique, du Grand-Duché de Luxembourg, du Nord de la France et des Régions voisines (Ptéridophytes et Spermatophytes). Cinquième édition. Jardin botanique national de Belgique, Meise: CXXX + 1167 p.
Lammers T.G. (2007a) Campanulaceae. In: Kadereit J.W. & Jeffrey C. (eds.), The families and genera of vascular plants, vol. 8. Springer Verlag, Berlin: 26-56.
Lammers T.G. (2007b) World checklist and bibliography of Campanulaceae. Kew Publishing: 675 p.
Lewis P. & Lynch M. (1998) Campanulas: a gardener’s guide. Timber Press, Incorporated: 176 p.
Liveri E., Crowl A.A. & Cellinese N. (2019) Past, present, and future of Campanula (Campanulaceae) systematics-a review. Bot. Chron. 22: 209-222. [available online at: https://www.researchgate.net/publication/336471570_Past_present_and_futu...
Sell P. & Murrell G. (2006) Flora of Great Britain and Ireland. Vol. 4 Campanulaceae – Asteraceae. Cambridge University Press, Cambridge: XXVIII + 624 p.
Stace C. (1997) New flora of the British Isles, 2nd ed.: XXVII + 1130 p. Cambridge University Press.