Abstract
Floral development and inflorescence structure within Streptocarpus and Saintpaulia were investigated using Scanning Electron Microscopy (SEM). We discuss the structure and development of the pair-flowered cyme and the floral ontogeny found in the Gesneriaceae in a phylogenetic context with particular reference to an East African clade of Streptocarpus and Saintpaulia. Current phylogenetic hypotheses divide the caulescent East African Streptocarpus species into two distinct clades, in relation to which the position of Saintpaulia is not yet clear. Variation in the branching of the inflorescence showed phylogenetic significance and included dichasial, monochasial and unbranched patterns. In four of the East African Streptocarpus species sampled a single lateral bracteole was present on the first to third axes, after which the inflorescence was ebracteolate. Our results indicate that there may be some link between bracteole suppression and an alteration in the order of sepal initiation. The loss or suppression of lateral bracteoles also appears to result in the precocious development of the lateral cyme meristem.
Similar content being viewed by others
References
Harrison C. J. (1998) Developmental genetics and evolution of plant form in Streptocarpus. MSc thesis, University of Edinburgh, Edinburgh, UK.
C. J. Harrison M. Möller Q. C. B. Cronk (1999) ArticleTitleEvolution and Development of floral diversity in Streptocarpus and Saintpaulia Ann. Bot. 84 49–60 Occurrence Handle10.1006/anbo.1999.0887
O. M. Hilliard B. L. Burtt (1971) Streptocarpus: an African plant study University of Natal Press Pietermaritzburg
L. Hufford (1995) ArticleTitlePatterns of ontogenetic evolution in perianth diversification of Besseya (Scrophulariaceae) Amer. J. Bot. 82 IssueID5 655–680 Occurrence Handle10.2307/2445424
D. R. Maddison W. P. Maddison (2000) MacClade, version 4.0 Sinauer Associates Sunderland, Massachusetts
M. Möller Q. C. B. Cronk (1997) ArticleTitleOrigin and relationships of Saintpaulia (Gesneriaceae) based on ribosomal DNA internal transcribed spacer (ITS) sequences Amer. J. Bot. 84 IssueID7 956–965 Occurrence Handle10.2307/2446286
Möller M., Cronk Q. C. B. (2001a) Evolution of morphological novelty: a phylogenetic analysis of growth patterns in Streptocarpus (Gesneriaceae). Evolution 55(5): 918–929.
Möller M., Cronk Q. C. B. (2001b) Phylogenetic studies in Streptocarpus (Gesneriaceae): reconstruction of biogeographic history and distribution patterns. Syst. Geogr. Pl. 71: 545–555.
J. F. Smith J. C. Wolfram K. D. Brown C. L. Carroll D. S. Denton (1997) ArticleTitleTribal relationships in the Gesneriaceae: evidence from DNA sequences of the chloroplast gene ndhF Ann. Missouri Bot. Gard. 84 IssueID1 50–66 Occurrence Handle10.2307/2399953
J. F. Smith M. E. Kresge M. Möller Q. C. B. Cronk (1998) ArticleTitleA cladistic analysis of ndhF sequences from representative species of Saintpaulia and Streptocarpus subgenera Streptocarpus and Streptocarpella (Gesneriaceae) Edinburgh J. Bot. 55 IssueID1 1–11 Occurrence Handle10.1017/S0960428600004315
K. K. Smith (2001) ArticleTitleHeterochrony revisited: the evolution of developmental sequences Biol. J. Linn. Soc. 73 IssueID2 169–186 Occurrence Handle10.1006/bijl.2001.0535
K. K. Smith (2003) ArticleTitleTime's arrow: heterochrony and the evolution of development Int. J. Dev. Biol. 47 IssueID7–8 613–621 Occurrence Handle14756337
Y. Z. Wang (2001) ArticleTitleReversion of floral development under adverse ecological conditions in Whytockia bijieensis (Gesneriaceae) Austral. J. Bot. 49 IssueID2 253–258 Occurrence Handle10.1071/BT00002
Y. Z. Wang Z. Y. Li (2002) ArticleTitleInflorescence development of Whytockia (Epithemateae, Gesneriaceae) and phylogenetic implications within Gesneriaceae Pl. Syst. Evol. 236 IssueID1–2 45–54 Occurrence Handle10.1007/s00606-002-0234-9
A. Weber (1973) ArticleTitleDie Struktur der paarblütigen Partialfloreszenzen der Gesneriaceen und bestimmter Scrophulariaceen Beitr. Biol. Pflanzen 49 IssueID3 429–460
A. Weber (1978) ArticleTitleTransitions from pair-flowered to normal cymes in Gesneriaceae Notes Roy. Bot. Gard. Edinburgh 36 IssueID2 355–368
A. Weber (1982) ArticleTitleEvolution and radiation of the pair-flowered cyme in Gesneriaceae Austral. Syst. Bot. Soc. Newsl. 30 23–41
A. Weber (1995) ArticleTitleDevelopmental aspects of the pair-flowered cyme of Gesneriaceae Gesneriana 1 IssueID1 18–28
Weber A. (2004) Gesneriaceae. In: Kubitzki K., Kadereit J. W. (eds.) The families and genera of vascular plants. Springer Berlin, pp. 63–158.
H. Wiehler (1983) ArticleTitleA synopsis of the neotropical Gesneriaceae Selbyana 6 IssueID1–4 1–219
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Haston, E., De Craene, L. Inflorescence and floral development in Streptocarpus and Saintpaulia (Gesneriaceae) with particular reference to the impact of bracteole suppression. Plant Syst. Evol. 265, 13–25 (2007). https://doi.org/10.1007/s00606-006-0494-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00606-006-0494-x