Cotoneaster

Wall cotoneaster Cotoneaster horizontalis, copyright Peganum.

Belongs within: Rosales.

Cotoneaster is a Palaearctic genus of trees and (more commonly) shrubs bearing usually red fruits (Hickman 1993).

The cotoneasters
Published 23 December 2007
Cotoneaster frigidus, from Wikipedia.

Cotoneaster is a genus of shrubs (occassionally small trees) native to the Palaearctic, but also present in other temperate areas as represented by weed species. As shown pretty well in the photo above, Cotoneaster is part of the Rosaceae and closely related to such genera as Crataegus (hawthorns) and Pyracantha (firethorns). Depending on how you look at it, Cotoneaster is a smallish genus or a rather large genus. The problem is that a number of polyploid lines of Cotoneaster are avid indulgers in apomixis, the asexual production of seed (plant parthenogenesis). The resulting shortage of genetic recombination means that there is almost no theoretical limit to how minutely the ‘species’ can be divided, and a whole host of ‘microspecies’ of perhaps dubious practicality potentially can be (and often have been) identified. The situation is even further complicated in many plants such as Cotoneaster that are not obligate apomicts—Cotoneaster flowers remain attractive to wasps, and a very low level of sexual reproduction may still occur. Most authors, though, continue to define their Cotoneaster ‘species’ fairly broadly, in a victory for pragmatism over precision.

Characters (from Hickman 1993): Shrub or tree, unarmed. Leaves stipuled, petioled, subevergreen, entire. Flowers solitary or clustered at branch tips. Bractlets on hypanthium absent; sepals persistent; stamens about 20; ovary inferior, 2–5-chambered, styles 2–5, free. Fruit a pome, drupe-like.

Systematics of Cotoneaster
<==Cotoneaster
    |--C. adpressusO88
    |--C. congestusO88
    |--C. duthieanusO88
    |--C. franchetiiH06
    |--C. glaucophyllusH90
    |--C. horizontalisNPA01
    |--C. integerrimus Medikus 1793 (see below for synonymy)TR03
    |--C. ludlowiiO88
    |--C. mathonnetii Gandoger 1875TR03
    |--C. microphyllusO88
    |--C. obtususV09
    |--C. pannosaH93
    |--C. rotundifoliusH90
    |--C. sanguineusO88
    |--C. sherriffiiO88
    |--C. simonsiiH59
    |--C. tomentosaC55
    `--C. zayulensisO88

Cotoneaster integerrimus Medikus 1793 [=Mespilus cotoneaster Linnaeus 1753, C. vulgaris Lindley 1822; incl. C. scandinavicus Hylmö 1993]TR03

*Type species of generic name indicated

References

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 1. Librairie de Victor Masson: Paris.

[H90] Harden, G. J. (ed.) 1990. Flora of New South Wales vol. 1. New South Wales University Press.

[H59] Healy, A. J. 1959. Contributions to a knowledge of the adventive flora of New Zealand, no. 7. Transactions of the Royal Society of New Zealand 86 (1): 113–118.

[H06] Henderson, L. 2006. Comparisons of invasive plants in southern Africa originating from southern temperate, northern temperate and tropical regions. Bothalia 36 (2): 201–222.

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[NPA01] Nuzzaci, G., A. Di Palma & P. Aldini. 2001. Functional morphology and fine structure of the female genital system in Typhlodromus spp. (Acari: Phytoseiidae). In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 196–202. CSIRO Publishing: Melbourne.

[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: an introductory note. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 19–46.

[TR03] Thulin, M., & S. Ryman. 2003. Proposal to conserve the name Mespilus cotoneaster (Rosaceae) with a conserved type. Taxon 52: 371–372.

[V09] Verdcourt, B. (ed.) 2009. Additions to the wild fauna and flora of the Royal Botanic Gardens, Kew. XXVI. Miscellaneous records. Kew Bulletin 64 (1): 183–194.

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