Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-08T02:57:56.906Z Has data issue: false hasContentIssue false

Geoxylic suffrutices of African savannas: short but remarkably similar to trees

Published online by Cambridge University Press:  13 July 2017

Pierre Meerts*
Affiliation:
Laboratoire d'Ecologie végétale et Biogéochimie, Université Libre de Bruxelles, Avenue F.D. Roosevelt 50 CP 244, B-1050 Brussels, Belgium
*
*Corresponding author. Email: [email protected]

Abstract:

In southern African savannas, geoxylic suffrutices or ‘underground trees’ attain only a hundredth to a tenth the height of normal trees, but other traits have received little attention. Geoxylic suffrutices and congeneric trees were compared for minimum and maximum values of seven morphological traits. Thirty-six geoxyle-tree pairs co-occurring in Katanga (Democratic Republic of the Congo) were compared, based on data from standard floras. The tree/geoxyle ratio ranged from 0.92 to 1.67 and was greater than 1 in 12 of 14 trait comparisons. However, the difference was significant in only five comparisons. Reproductive traits generally did not differ. The maximal value of leaf traits (lamina length, lamina width, petiole length) was 33–67% greater in trees. The morphological traits of geoxyles are not much altered compared with their tree counterparts, especially for reproductive traits. For vegetative traits, geoxyles express a restricted part of the phenetic space of trees, being unable to attain trait values as high as those of their tree congeners. However, unlike bonsais or alpine dwarfs, the leaves of geoxyles are not much smaller compared with normal trees.

Type
Short Communication
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

LITERATURE CITED

BURTT DAVY, J. 1922. The suffrutescent habit as an adaptation to environment. Journal of Ecology 10:211219.CrossRefGoogle Scholar
BYNG, J. W. 2013. Systematics of Syzygium (Myrtaceae) from Africa and the Indian Ocean region. PhD thesis, University of Aberdeen, UK.Google Scholar
CHISUMPA, S. M. & BRUMMITT, R. K. 1987. Taxonomic notes on tropical African species of Protea . Kew Bulletin 42:815853.CrossRefGoogle Scholar
DAVIES, T. J., DARU, B. H., VANDER BANK, M., MAURIN, O. & BOND, W. J. 2016. Multiple routes underground? Frost alone cannot explain the evolution of underground trees. New Phytologist 209:910912.CrossRefGoogle ScholarPubMed
DE WILDEMAN, E. 1933. Le port suffrutescent dépend des facteurs de l'ambiance. Institut Royal Colonial Belge, section des Sciences Naturelles et Médicales, Mémoires I (4):151.Google Scholar
DUVIGNEAUD, P. 1951. Une érythrine à xylopode des steppes du Kwango. Lejeunia 15:9194.Google Scholar
DUVIGNEAUD, P. 1958. La végétation du Katanga et de ses sols métallifères. Bulletin de la Société Royale de Botanique de Belgique 90:127286.Google Scholar
FINCKH, M., REVERMANN, R. & AIDAR, M. P. M. 2016. Climate refugees going underground – a response to Maurin et al. (2014). New Phytologist 209:904909.CrossRefGoogle ScholarPubMed
JONES, S. W. 1980. Morphology and major taxonomy of Garcinia (Guttiferae). PhD thesis, University of Leicester, UK.Google Scholar
KÖRNER, C., NEUMAYER, M., PELAEZ MENENDEZ-RIEDL, S. & SMEETS-SCHEEL, A. 1989a. Functional morphology of mountain plants. Flora 182:353383.CrossRefGoogle Scholar
KÖRNER, C., PELAEZ MENENDEZ-RIEDL, S. & JOHN, P.C.L. 1989b. Why are bonsai plants small? A consideration of cell size. Australian Journal of Plant Physiology 16:434448.Google Scholar
LACHENAUD, O. 2013. Le genre Psychotria (Rubiaceae) en Afrique occidentale et centrale: taxonomie, phylogénie et biogéographie. PhD thesis, Université Libre de Bruxelles, Belgium.Google Scholar
MAURIN, O., CHASE, M. K., JORDAAN, M. & VAN DER BANK, M. 2010. Phylogenetic relationships of Combretaceae inferred from nuclear and plastid DNA sequence data: implications for generic classification. Botanical Journal of the Linnean Society 162: 453476.CrossRefGoogle Scholar
MAURIN, O., DAVIES, T. J., BURROWS, J. E., DARU, B. H., YESSOUFOU, K., MUASYA, A. M., VAN DER BANK, M. & BOND, W. J. 2014. Savanna fire and the origins of the ‘underground forests’ of Africa. New Phytologist 204:201214.CrossRefGoogle ScholarPubMed
MEERTS, P. 2015. An annotated checklist to the trees and shrubs of the Upper Katanga (D.R. Congo). Phytotaxa 258:201250.CrossRefGoogle Scholar
MEERTS, P. & HASSON, M. 2016. Arbres et arbustes du Haut-Katanga. Jardin botanique, Meise. 386 pp.Google Scholar
MULTIPLE AUTHORS. 1948–1987. Flore d'Afrique centrale [Published with different titles]. Jardin Botanique National de Belgique, Meise.Google Scholar
MULTIPLE AUTHORS. 1960–2006. Flora Zambesiaca. Royal Botanic Gardens, Kew.Google Scholar
NIKLAS, K. J. 1994. Plant allometry. The scaling of form and processes. The University of Chicago Press, Chicago. 412 pp.Google Scholar
SCHMITZ, A. 1971. La végétation de la plaine de Lubumbashi. Série scientifique 113. Institut national pour l’étude agronomique du Congo, Bruxelles. 388 pp.Google Scholar
WHITE, F. 1977. The underground forests of Africa: a preliminary review. Gardens’ Bulletin, Singapore 24:5771.Google Scholar
WINTER, P. J. D. & VAN WYK, B.-E. 1996. A revision of the genus Heteromorpha (Apiaceae). Kew Bulletin 51:225265.CrossRefGoogle Scholar