Saxifraga

This article is about the plant genus. For other uses, see Saxifrage (disambiguation).

Saxifraga
Saxifraga cochlearis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Core eudicots
Order:	Saxifragales
Family:	Saxifragaceae
Genus:	Saxifraga L.
Sections
Ciliatae Cotylea Cymbalaria Gymnopera Heterisia Irregulares Ligulatae Merkianae Mesogyne Micranthes Odontophyllae Porphyrion Saxifraga Trachyphyllum Xanthizoon
Synonyms
Boecherarctica Á.Löve Cascadia A.M.Johnson Micranthes Haw. Zahlbrucknera Rchb.

Saxifraga is the largest genus in the family Saxifragaceae, containing about 440 species of Holarctic perennial plants, known as saxifrages. The Latin word saxifraga means literally "stone-breaker", from Latin saxum ("rock" or "stone") + frangere ("to break"). It is usually thought to indicate a medicinal use for treatment of urinary calculi, rather than breaking rocks apart.

The genera Saxifragopsis (saxifragopsises), Saxifragella are sometimes included in Saxifraga. In recent DNA based phylogenetic analyses of the Saxifragaceae, the sections Micranthes and Merkianae are shown to be more closely related to the Boykinia and Heuchera clades, and the most recent floras separate these groups as the genus Micranthes.

Description

Round-leaved Saxifrage (S. rotundifolia), whose sticky leaves seem to catch small invertebrates

Most saxifrages are smallish plants whose leaves grow close to the ground, often in a rosette. The leaves typically have a more or less incised margin; they may be succulent, needle-like and/or hairy, reducing evaporation.^{[citation needed]} Charles Darwin – erroneously believing Saxifraga to be allied to the sundew family (Droseraceae) – suspected the sticky-leaved Round-leaved Saxifrage (S. rotundifolia), Rue-leaved Saxifrage (S. tridactylites) and Pyrenean Saxifrage (S. umbrosa) to be protocarnivorous plants and conducted some experiments whose results supported his observations, but the matter has apparently not been studied since his time.^{[citation needed]}

The inflorescences or single flowers are raised above the main plant body at flowering time on stalks devoid of true leaves.^{[citation needed]} The small actinomorphic hermaphrodite flowers have five petals and sepals and are usually white, but red to yellow in some species.^{[citation needed]} As in other primitive eudicots, some of the 5 or 10 stamens may appear petal-like.^{[citation needed]}

Ecology

Saxifrages are typical inhabitants of Arctic-alpine ecosystems, and are hardly ever found outside the temperate parts of the Northern Hemisphere; most members of this genus are found in subarctic climates.^{[citation needed]} A good number of species grow in glacial habitat, such as S. biflora which can be found some 4,000 metres (13,000 ft) above sea level in the Alps, or the East Greenland Saxifrage (S. nathorstii).^{[citation needed]} The genus is also abundant in the Eastern and Western Himalayan alpine shrub and meadows.^{[citation needed]} Though the archetypal saxifrage is a small plant huddling between rocks high up on a mountain,^{[citation needed]} many species do not occur in such habitat and are larger (though still rather delicate) plants found on wet meadows.

Various Saxifraga species are used as food plants by the caterpillars of some butterflies and moths, such as the Phoebus Apollo (Parnassius phoebus).

Use by humans

Pyrenean Saxifrage (S. umbrosa), ancestor to horticultural hybrid saxifrages

S. × urbium, the hybrid between Pyrenean Saxifrage (S. umbrosa) and Saint Patrick's Cabbage (S. spathularis), is known as London Pride and commonly grown as an ornamental plant. Another horticultural hybrid is Robertsoniana Saxifrage (S. × geum), derived from Kidney Saxifrage (S. hirsuta) and Pyrenean Saxifrage.^{[citation needed]} Some wild species are also used in gardening. Saxifrages are popular cushion plants for rock gardens in temperate and cold climates. Cambridge University Botanic Garden hosts the United Kingdom's national collection of saxifrages.

Purple Saxifrage (S. oppositifolia) is a popular floral emblem. It is the territorial flower of Nunavut (Canada) and the county flower of County Londonderry in the UK.^{[citation needed]} Known as rødsildre ("red saxifrage") in Norway, it also is the county flower of Nordland.^{[citation needed]} Tsukuba in Japan has as its city flower hoshizaki-yukinoshita (Katakana: ホシザキユキノシタ), the aptera form of Creeping Saxifrage (S. stolonifera).^{[citation needed]} The leaves of the Japanese variety "yukinoshita" (literally "Under the snow") can also been eaten, and is consumed at least within the large southern island of Kyushu. It is prepared by frying the younger succulent leaves in tempura batter.^{[citation needed]}

In literature, saxifrages do not figure prominently – that is, outside scientific writing such as the studies of Adolf Engler or the landmark The Structure and Biology of Arctic Flowering Plants. White Mountain Saxifrage (S. paniculata) is discussed in Nicholas Culpeper's 1652 herbal The English Physitian.^{[citation needed]} Well-known references to saxifrages in literature are:

• In William Carlos Williams' poem "A Sort of a Song", Williams refers to his idea of perception (to see through the metaphorical rock, see into the essence of the object, "no ideas but in things") when he writes Invent! Saxifrage is my flower that splits the rocks.^{[citation needed]}
• In Kim Stanley Robinson's Mars trilogy, the character Sax Russell – an atomic physicist sent to Mars as part of Earth's first colony attempt on that planet – is named after this plant. There are several references to the saxifrage genus, and Robinson uses the plant's common name "stonebreaker" and descriptions of the flower to describe aspects of Russell's personality.^{[citation needed]}
• In The Song of Bernadette, Franz Werfel described Saint Bernadette Soubirous as eating saxifrage in response to a request from Our Lady of Lourdes to "eat of the plants" near where she was about to dig for the Lourdes Spring. The real Saint Bernadette did eat plants and said "the lady" had asked her to. Several devotional writers identified the plants as saxifrage, and the location of the Lourdes Grotto, in a huge outcropping in the Pyrenees, makes it plausible.^{[citation needed]}

Selected species

Saxifraga caesia

Lesser London Pride (Saxifraga cuneifolia)

Saxifraga decipiens

Northwestern Saxifrage (Saxifraga integrifolia)

Irish Saxifrage (Saxifraga rosacea)

Tolmie's Saxifrage (Saxifraga tolmiei)

Prickly Saxifrage (Saxifraga tricuspidata) flowers

• Saxifraga adscendens – Ascending Saxifrage
• Saxifraga aizoides – Yellow Mountain Saxifrage, Yellow Saxifrage
• Saxifraga aizoon
• Saxifraga algisii
• Saxifraga anadyrensis
• Saxifraga androsacea
• Saxifraga aquatica
• Saxifraga aprica – Sierra Saxifrage
• Saxifraga arachnoidea
• Saxifraga aspera
• Saxifraga biflora
• Saxifraga bronchialis L. – Matte Saxifrage
• Saxifraga bryophora
• Saxifraga caesia
• Saxifraga californica
• Saxifraga callosa Sm.
• Saxifraga canaliculata
• Saxifraga careyana
• Saxifraga carpatica
• Saxifraga cernua – Drooping Saxifrage, Nodding Saxifrage, Bulblet Saxifrage
• Saxifraga cervicornis
• Saxifraga cespitosa – Tufted Saxifrage
• Saxifraga ciliata
• Saxifraga cochlearis
• Saxifraga columnaris Schmalh.
• Saxifraga corsica
• Saxifraga cuneifolia – Lesser London Pride
• Saxifraga cymbalaria – Celandine Saxifrage
• Saxifraga decipiens
• Saxifraga dinnikii Schmalh.
• Saxifraga eschscholtzii – Cushion Saxifrage
• Saxifraga exarata
• Saxifraga ferruginea Graham – Rustyhair Saxifrage
• Saxifraga flagellaris Willd. ex Sternb. – Whiplash Saxifrage, Spider Saxifrage, "spider plant"
• Saxifraga florulenta
• Saxifraga foliolosa – Leafy Saxifrage
• Saxifraga forbesei
• Saxifraga fortunei Hook.f.
• Saxifraga gaspensis – Gaspé Saxifrage
• Saxifraga × geum – Robertsoniana Saxifrage (S. hirsuta × S. umbrosa)
• Saxifraga granulata – Meadow Saxifrage
• Saxifraga groenlandica
• Saxifraga hederacea
• Saxifraga hieracifolia – Hawkweed-leaved Saxifrage, Stiff-stemmed Saxifrage
• Saxifraga hirculus L. – Yellow Marsh Saxifrage, Marsh Saxifrage, "bog saxifrage"
• Saxifraga hirsuta – Kidney Saxifrage
• Saxifraga howellii
• Saxifraga hyperborea – Pygmy Saxifrage
• Saxifraga hypnoides – Mossy Saxifrage, Dovedale Moss
• Saxifraga integrifolia – Northwestern Saxifrage
• Saxifraga juniperifolia
• Saxifraga korshinskii Kom.
• Saxifraga lactea Turcz.
• Saxifraga longifolia
• Saxifraga lyallii Engl. – Redstem Saxifrage
• Saxifraga mertensiana – Mertens' Saxifrage
• Saxifraga michauxii – Michaux's Saxifrage
• Saxifraga micranthidifolia – Brook Lettuce
• Saxifraga montana
• Saxifraga moschata – Musky Saxifrage, "mossy saxifrage"
  • Saxifraga moschata ssp. basaltica
• Saxifraga muscoides
• Saxifraga mutata
• Saxifraga nathorstii (Dusén) Hayek – East Greenland Saxifrage
• Saxifraga nelsoniana D.Don – Heartleaf Saxifrage
• Saxifraga nidifica – Peak Saxifrage, "alpine saxifrage"
• Saxifraga nipponica
• Saxifraga nivalis – Snow Saxifrage, "alpine saxifrage"
• Saxifraga occidentalis – Western Saxifrage
• Saxifraga odontoloma Piper – Streambank Saxifrage
• Saxifraga oppositifolia – Purple Saxifrage, Purple Mountain Saxifrage
• Saxifraga oregana Howell – Bog Saxifrage
• Saxifraga osloensis Knaben - Oslo Saxifrage, a natural hybrid species
• Saxifraga paniculata – White Mountain Saxifrage
• Saxifraga pensylvanica L. – Swamp Saxifrage
• Saxifraga petraea
• Saxifraga platysepala (= S. flagellaris auct. non Willd.) – Broadsepal Saxifrage
• Saxifraga porophylla
• Saxifraga razshivinii – Razshivin's Saxifrage
• Saxifraga redofskii – Many-flower Saxifrage
• Saxifraga reflexa – Yukon Saxifrage
• Saxifraga rhomboidea – Diamondleaf Saxifrage
• Saxifraga rivularis – Alpine Brook Saxifrage, Brook Saxifrage, Highland Saxifrage
• Saxifraga rosacea – Irish Saxifrage
• Saxifraga rotundifolia L. – Round-leaved Saxifrage
• Saxifraga roylei
• Saxifraga rudolphiana
• Saxifraga rufidula – Redwool Saxifrage
• Saxifraga rufopilosa – Redhair Saxifrage
• Saxifraga sancta
• Saxifraga serpyllifolia – Thymeleaf Saxifrage
• Saxifraga sibirica – Siberian Saxifrage
• Saxifraga spathularis – Saint Patrick's Cabbage
• Saxifraga spicata – Spiked Saxifrage
• Saxifraga stellaris – Starry Saxifrage, Star Saxifrage
• Saxifraga stolonifera – Creeping Saxifrage, Strawberry Saxifrage, Creeping Rockfoil, Strawberry Begonia, Strawberry Geranium, "Aaron's beard"
  • Saxifraga stolonifera f. aptera (Makino) H.Hara – hoshizaki-yukinoshita (Japanese)
• Saxifraga subverticillata
• Saxifraga taygetea
• Saxifraga taylorii – Taylor's Saxifrage
• Saxifraga tenella
• Saxifraga tenuis – Ottertail Pass Saxifrage
• Saxifraga tolmiei – Tolmie's Saxifrage
• Saxifraga tombeanensis
• Saxifraga tricuspidata Rottb. – Prickly Saxifrage
• Saxifraga tridactylites – Rue-leaved Saxifrage, "nailwort"
• Saxifraga trifurcata
• Saxifraga × urbium – London Pride (S. spathularis × S. umbrosa)
• Saxifraga umbrosa – Pyrenean Saxifrage
• Saxifraga vandelli
• Saxifraga virginiensis – Early Saxifrage, Virginia Saxifrage
• Saxifraga wahlenbergii

Formerly placed here

Plants formerly placed in Saxifraga are mainly but not exclusively Saxifragaceae. They include:^{[citation needed]}

• Astilboides tabularis, as S. tabularis
• Bergenia crassifolia, as S. cordifolia, S. crassifolia
• Bergenia pacumbis, as S. ligulata, S. pacumbis
• Bergenia purpurascens, as S. delavayi, S. purpurascens
• Boykinia jamesii, as S. jamesii
• Boykinia occidentalis (Coastal Brookfoam), as S. elata
• Boykinia richardsonii (Richardson's Brookfoam), as S. richardsonii
• Chondrosea cotyledon, as S. cotyledon
• Darmera peltata (Indian Rhubarb), as S. peltata
• Leptarrhena pyrolifolia, as S. pyrolifolia
• Luetkea pectinata (Partridgefoot), as S. pectinata
• Mukdenia rossii (Mukdenia), as S. rossii

Other "saxifragous" plants

Several plant genera have names referring saxifrages although they might not be close relatives of Saxifraga. They include:^{[citation needed]}

• Pyramidal Saxifrage, Chondrosea cotyledon
• Golden-saxifrages, Chrysosplenium
• Burnet-saxifrages, Pimpinella
• Pepper-saxifrage, Silaum silaus

Some plants refer to Saxifraga in their generic names or specific epithets, either because they are also "rock-breaking" or because they resemble members of the saxifrage genus:^{[citation needed]}

• Campanula saxifraga
• Celmisia saxifraga (Benth.) W.M.Curtis
• Cineraria saxifraga DC.
• Dryopteris saxifraga
• Petrorhagia saxifraga – Tunicflower
• Pimpinella saxifraga – Burnet Saxifrage
• Ptychotis saxifraga
• Saxifragella
• Saxifragodes
• Saxifragopsis Small

External links

• The Saxifrage Society
•  Chisholm, Hugh, ed. (1911). "wstitle=Saxifrage". Encyclopædia Britannica (11th ed.). Cambridge University Press.