Neotropical Cyrillaceae

Jovita Cislinski Yesilyurt

The Natural History Museum, London, UK. 

Description

Small to medium trees (3-8 m) or shrubs, usually evergreen; non-laticiferous. Leaves alternate, spirally arranged to usually clustered at the stem apex, simple, margin entire, pinnately veined, usually coriaceous; petiolate to sub-sessile; stipules present, caducous or absent (ligule or glandular structures sometimes present in the leaf axils), when present usually inconspicuous. Inflorescences aggregated in racemes, terminal or sometimes axillary. Flowers hermaphrodite, bracts and bracteoles present or absent, actinomorphic or slightly zygomorphic, pedicellate; sepals 5(-7), free or basally fused, the lobes about the same length as the tube, accrescent (often) or not; petals 5(-7) imbricate or contorted, free or basally connate, white or pink; hypogynous disk present, floral nectaries present, nectar secretion from the perianth (from the petals in Cyrilla Garden ex L.), or from the disk, or rarely from both intrastaminal, persistent; androecium of 5 or 10 free, equal or markedly unequal (outer whorl longer in Cliftonia Banks ex Gaertn.f.) stamens, alternating with the petals, the filaments sometimes flattened basally; anthers dorsifixed, versatile, dehiscing introrsely via pores (apical) or via short or long slits; gynoecium syncarpous, 2-5 carpelled, carpels number equal to the number of perianth parts, 2-5 locular, placentation axile to apical, with ovules 1-3 per locule, with or without a short style; stigma dry type; non-papillate. Fruit fleshy or non-fleshy, capsular-indehiscent or samara; seeds 1-5 without aril.

Notes on delimitation

  • In the APG system Cyrillaceae is placed in the Ericales as sister to Ericaceae, and also closely related to Clethraceae.
  • Purdiaea Planch. was formerly considered as a third genus in the family Cyrillaceae. However, recent research (Anderberg & Zhang 2002) has shown that this genus is better placed in the Clethraceae. Purdiaea is native to tropical regions of the Caribbean, Central America and northern South America.

Distribution in the Neotropics

  • Endemic to the Neotropics:  sub -tropical to tropical from southeastern U.S.A., through Central America and the Caribbean to northern South America.

Distinguishing characters (always present)

Other important characters

Number of genera

  • The family comprises two genera (Cyrilla and Cliftonia) each with a single species:  Cyrilla racemiflora L. and Cliftonia monophylla Britton & sec. Sargent.

Useful tips for generic identification

Key to genera of Neotropical Cyrillaceae

1.  Stamens 10; filaments basally flattened; fruits samara-like (2-5 winged) … Cliftonia
1.  Stamens 5; filaments terete; fruits berry -like (unwinged) … Cyrilla

Notable genera and distinguishing features

  • Several species or varieties of Cyrilla have been distinguished on the basis of local variation in leaf and inflorescence size.
  • J. L. Thomas (1960) acknowledges that C. racemiflora is polymorphic and should be recognized as a single variable species.
  • Yesilyurt (2009) pointed out that during studies of the flora of the Guianas that specimens showed considerable amount of variation in size and shape and even texture in all the features of the leaves, flowers and fruits.

Status

  • Native.

Important literature

Anderberg, A. A. & Zhang, Z. (2002). Phylogenetic relationships of Cyrillaceae and Clethraceae (Ericales) with special emphasis on the genus Purdiaea. Organisms, Div. & Evol. 2: 127-137. 

Thomas, J.L. (1960). A monographic study of the Cyrillaceae. Contr. Gray Herb. 186:1-114.

Yesilyurt, J.C. (2009). 71. Cyrillaceae. Flora of the Guianas 27: 1-6.  Royal Botanic Gardens, Kew.

How to cite

Yesilyurt, J.C. (2010). Neotropical Cyrillaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Cyrillaceae.htm.