| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Guamatelaceae S.H. Oh & D. Potter

~ Rosaceae-Neillieae.

Habit and leaf form. Shrubs. Leaves opposite; without marked odour; simple. Lamina entire; cordate- ovate (white-tomentose below); palmately veined; cordate. Leaves stipulate. Stipules intrapetiolar; free of one another; setaceous; persistent.

Reproductive type, pollination. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes. The ultimate inflorescence units racemose. Inflorescences terminal; terminal racemes. Flowers bracteate (the bracts filiform); regular; 5 merous; cyclic; tetracyclic. Free hypanthium present (short), or absent (“the petals inserted at the mouth of the calyx tube”).

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; shortly gamosepalous; lobed. Calyx lobes markedly longer than the tube. Calyx regular; imbricate. Corolla 5; polypetalous; red, or pink.

Androecium 10. Androecial members free of the perianth; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens 10; diplostemonous; both alternating with and opposite the corolla members; filantherous. Anthers cordate-ovate; apiculate.

Gynoecium 3 carpelled (but only one component maturing, according to Hutchinson). Carpels reduced in number relative to the perianth. The pistil with the gynoecium interpreted as transiently syncarpous, 3 celled. Gynoecium ambigously syncarpous (the pistils being at first united by the stigmas), or apocarpous; depending on interpretation, eu-apocarpous, or synstylous; superior. Carpel stylate; apically stigmatic. Styles united to free (“mostly free at anthesis”). Carpel 5–50 ovuled (? - “several”). Placentation marginal (the ovules biseriate on the adaxial suture). Ovary if treated as syncarpous, 5–50 locular (?). Gynoecium stylate. Styles 3; partially joined; apical. Ovules arillate.

Fruit non-fleshy; an aggregate (sometimes comprising more than one carpel?), or not an aggregate. The fruiting carpel dehiscent; a follicle. Fruit with “numerous” seeds, according to Hutchinson, despite the ovules “several” per carpel. Seeds non-endospermic. Cotyledons 2. Testa shining, bony , smooth.

Geography, cytology. Neotropical. Guatemala, Honduras and Mexico.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rosiflorae; Rosales (in Rosaceae). Cronquist’s Subclass Rosidae; Rosales (in Rosaceae). APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Crossosomatales.

Species 1. Genera 1; Guamatela (G. tuerckheimii).

History of the encoded description. This draft description by LW (2009) lacks information on anatomy, anther development, pollen form, embryology, and phytochemistry. It also needs pursuing further with reference to features characteristic of Rosaceae.

Illustrations. • Guamatela tuerckheimii: herbarium sheet (Smithsonian, BHL).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 8th June 2026. delta-intkey.com’.

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