Saxifragaceae Juss.

First published in Gen. Pl. [Jussieu] 308. 1789 [4 Aug 1789] (as "Saxifragae") (1789)nom. cons.
This family is accepted

Descriptions

Saxifragaceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit
Herbs, not or slightly succulent
Morphology Leaves
Leaves usually alternate (opposite in Vahlia), exstipulate
Morphology Reproductive morphology Flowers
Flowers actinomorphic, hermaphrodite, rarely solitary
Morphology Reproductive morphology Flowers Calyx
Sepals usually 5, imbricate or valvate
Morphology Reproductive morphology Flowers Corolla
Petals alternate with the sepals or absent, often clawed, perigynous or rarely epigynous
Morphology Reproductive morphology Flowers Androecium
Stamens inserted with the petals, 5–10; filaments free; anthers 2-celled, dehiscing longitudinally
Morphology Reproductive morphology Flowers Gynoecium
Ovary 1–5-celled, free or adnate to the receptacle; styles usually free; ovules numerous, on axile or parietal placentas or the latter pendulous from the apex of the cells
Morphology Reproductive morphology Fruits
Fruit a capsule
Morphology Reproductive morphology Seeds
Seeds usually numerous, small, with endosperm; embryo minute, straight
Distribution
Widely distributed in temperate regions, rare in the tropics
[FWTA]

Zappi, D. (2009). Neotropical Saxifragaceae.

Morphology
Description

Perennial herbs, often growing together and forming mats. Leaves simple , alternate and basal , rosulate, or rarely opposite, without stipules (stipules sometimes represented by expanded margins of sheathing petiolar leaf bases), entire or deeply lobed to rarely compound , margin often crenate , venation pinnate or often palmate . Inflorescence axillary to terminal , racemose or cymose, bracteate. Flowers showy, hermaphrodite , actinomorphic , rarely zygomorphic , bracteolate; sepals (3-)5, free ; petals (3-)5, often clawed and dissected , white or cream-coloured, rarely pink; stamens 3-10, free , anthers 2-locular; intrastaminal disk present, ovary inferior to superior , 2(-3) carpelate, carpels connate towards base forming a compound , deeply lobed ovary , lobes prolonged into stylar beaks terminated by a capitate stigma , placentation variously axile and parietal , ovules numerous.  Fruit capsular, dry, septicidal or dehiscing along ventral suture of carpels above level of union; seeds numerous, small.

Distribution
Distribution in the Neotropics
  • In the Neotropics, the Saxifragaceae is quite a marginal family with a few genera occurring at high altitude and reaching Mexico from the West of the USA.
  • Heuchera L. - widespread through North America to C. Mexico, 5-6 species.
  • Jepsonia Small - endemic to California and Baja California, 2-3 species.
  • Saxifraga L. - North temperate regions of the world, in America it occurs in Mexico and in the Andes to Cape Horn and Falkland Islands, 6-7 species.
  • Hieronymusiaalchemilloides (Griseb.) Engler - monospecific, formerly placed in Suksdorfia, North America into N. California; Andes of S. Bolivia and NW Argentina.
  • Tetillahydrocotylifolia DC. - monospecific, Chile.
Diagnostic
Key differences from similar families
  • Vegetatively resembles the Gentianaceae, Apiaceae, Violaceae and other alpine plants found in the Andes, being distinguished from them by its corolla with five distinct petals, stamens 1 or 2 x the number of petals.
  • It can be confused with the Crassulaceae, but these are succulent and have carpels totally distinct and generally present in larger number (4 or +).
Other important characters
  • Intra-staminal nectar disk.
  • Carpels projected into stylar beaks terminated by capitatestigma.
Distinguishing characters (always present)
  • Perennial herbs.
  • Leaves mostly rosulate, margin crenate or lobed.
  • Flowers 5-merous, petals clawed and often fimbriate.
  • Ovary inferior to superior generally with 2 carpels not fused to the top.
  • Fruits capsular with many seeds.
General Description
Status
  • The few genera present in the Neotropics are associated with highlands, and there are a few cultivated species of Heuchera from Mexico, but this is not expressive in the tropics and does not naturalize. Endemic genera are Tetilla, which occurs only in Chile, and Jepsonia in California reaching Baja California.
Number of genera

Six genera (See Distribution) of which Tetilla is not strictly Neotropical.

Notes on delimitation
  • In former classifications, the Saxifragaceae used to include not only herbaceous but also woody genera that are nowadays included in other families (Escalloniaceae, Hydrangeaceae, Grossulariaceae). The present circumscription stems from molecular studies that support the Saxifragaceae s.s. (APG II, 2003, Soltis in Smith et al. 2004).
Literature
Important literature

APG II, 2003. An update of the Angiosperm Phylogeny group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141(4): 399-436.

Soltis, D.E. 2004. Saxifragaceae, pp. 346-348. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D. and Heald, S.V. (eds.). Flowering Plants of the Neotropics. New York Botanical Garden, Princeton University Press, Princeton.

[NTK]

Gemma Bramley, Anna Trias-Blasi & Richard Wilford (2023). The Kew Temperate Plant Families Identification Handbook. Kew Publishing Royal Botanic Gardens, Kew

Recognition
Characters of similar families: Crassulaceae: succulent stems and leaves, some shrubs, stipules absent, ovary superior or partly inferior, fruit a follicle. Ranunculaceae: stipules absent or minute, stamens numerous and arranged in whorls, fruit an achene, follicle or berry.
Morphology General Habit
Perennial herbs, rarely annual or biennial, often rhizomatous
Morphology Leaves Stipules
Stipules usually present or leaf bases sheathing
Morphology Leaves
Leaves usually in a basal rosette, sometimes cauline, usually alternate, simple or compound,- rarely peltate (Darmera), venation pinnate or sometimes palmate, margins entire, lobed, crenate or toothed, sometimes with lime-secreting hydathodes
Morphology Reproductive morphology Inflorescences
Inflorescence terminal, bracteate, cymose to racemose, occasionally solitary flowers
Morphology Reproductive morphology Flowers
Flowers usually actinomorphic, sometimes zygomorphic, usually bisexual, homostylous (heterostylous in Jepsonia), hypanthium free or partly fused with the ovary
Morphology Reproductive morphology Flowers Calyx
Calyx lobes (3–)5(–10), fused with the hypanthium
Morphology Reproductive morphology Flowers Corolla
Petals (4–)5(– 6) or absent, clawed, rarely cleft or dissected
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens usually 5 or 10, free, anthers basifixed
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary inferior or semi-inferior, carpels 2 or rarely 3, each carpel topped with a stylodium and capitate stigma
Morphology Reproductive morphology Fruits
Fruit a capsule, seeds generally small and numerous, rarely winged.
Distribution
35 genera and ca. 640 species. Widespread in temperate, arctic and alpine regions of the northern hemisphere and S America. Historically, Saxifragaceae contained genera that are now segregated into other families, including Hydrangeaceae and Grossulariaceae.
Note
Perennial herbs, rarely annual or biennial. Leaves alternate, in a basal rosette. Inflorescence terminal, cymous to racemous, rarely solitary. Petals usually 5 or absent. Stamens 5 or 10, Fruit a capsule.
Description Author
Richard Wilford
[KTEMP-FIH]

Uses

Use
Genera such as Saxifraga, Heuchera and Astilbe contain popular ornamental plants.
[KTEMP-FIH]

Sources

  • Flora of West Tropical Africa

    • Flora of West Tropical Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Herbarium Catalogue Specimens

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Neotropikey

    • Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
    • http://creativecommons.org/licenses/by/3.0
  • The Kew Temperate Plant Families Identification Handbook

    • The Kew Temperate Plant Families Identification Handbook
    • http://creativecommons.org/licenses/by-nc-sa/3.0