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40-431: See text Saxifragaceae is a family of herbaceous perennial flowering plants , within the core eudicot order Saxifragales. The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis. The family is divided into ten clades , with about 640 known species in about 35 accepted genera . About half of these consist of a single species, but about 400 of

80-458: A DNA study showed that Lepuropetalon and Parnassia were much closer to each other than to any others. This was the first DNA study to give strong statistical support (98% bootstrap support) for this relationship. In 2005, a study of flower structure concluded that the family Parnassiaceae belonged in the order Celastrales with Lepidobotryaceae , and a broadly defined Celastraceae , including Mortonia and Pottingeria . In 2006,

120-493: A family of flowering plants in the eudicot order Celastrales . The family is not recognized in the APG III system of plant classification . When that system was published in 2009, Parnassiaceae were treated as subfamily Parnassioideae of an expanded family Celastraceae . Parnassiaceae have only two genera , Lepuropetalon and Parnassia . Lepuropetalon has only one species , Lepuropetalon spathulatum ,

160-462: A winter annual that usually prefers sandy soil . It is one of the smallest of flowering plants, up to 2 cm tall. Lepuropetalon has a disjunct distribution , being known from the southeastern United States and central Chile , but is probably far more common than has been reported. Parnassia is a genus of perennial herbs , up to 60 cm tall, that grow in bogs , marshes , and other wet areas, mostly in cool to cold climates of

200-455: A study of DNA sequences confirmed that Lepuropetalon and Parnassia form a strongly supported clade . This study also showed strong support for a pentatomy consisting of Pottingeria , Mortonia , Parnassiaceae, and two clades of genera from Celastraceae as that family had been circumscribed in APG II . The relationships between these five clades remain unresolved. In 2009,

240-405: A woody stem, allowing plants to grow tall and transport water and nutrients over longer distances within the plant body. Since most woody plants are perennials with a longer life cycle because it takes more time and more resources (nutrients and water) to produce persistently living lignified woody stems, they are not as able to colonize open and dry ground as rapidly as herbs. The surface of herbs

280-475: Is ephemeral and often seasonal in duration. By contrast, non-herbaceous vascular plants are woody plants that have stems above ground that remain alive, even during any dormant season, and grow shoots the next year from the above-ground parts – these include trees , shrubs , vines and woody bamboos . Banana plants are also regarded as herbaceous plants because the stem does not contain true woody tissue. Some herbaceous plants can grow rather large, such as

320-400: Is a catalyst for dew, which in arid climates and seasons is the main type of precipitation and is necessary for the survival of vegetation, i.e. in arid areas, herbaceous plants are a generator of precipitation and the basis of an ecosystem. Most of the water vapor that turns into dew comes from the air, not the soil or clouds. The taller the herb ( surface area is the main factor though),

360-655: Is distinguished by being referred to as Saxifragaceae sensu stricto ( s.s. ), corresponding to the Saxifragoideae a natural monophyletic group. Historically, the Saxifragaceae has been placed in either the orders Rosales or Saxifragales . This reduced Saxifragaceae, corresponding to subfamily Saxifragoideae and its 30 genera, is now placed within the Saxifragales. There, with three other subfamilies (Ribesoideaee, Iteoideae and Pterostemonoideae) it forms

400-401: Is inferior to semi-inferior with two (sometimes three) carpels usually fused at the base, sometimes free, each topped with stylodium and capitate stigma. The ovules are few to many, with axile or parietal placentation and two to three styles . The fruit is usually a septicidal capsule or follicle, with numerous small seeds . Saxifragaceae has long been considered in a pivotal position in

440-444: Is placed on a hypanthium that may be free or may be partly fused with the ovary (which is then semi-inferior). There are usually five sepals , but there may be three to ten, fused with the hypanthium, occasionally petaloid. The petals are clawed, sometimes cleft at the tip or finely dissected. Flowers have five to ten stamens , free and opposite the petals, with the anthers usually basifixed and opening by lengthwise slits. The ovary

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480-576: Is terminated by a large globular gland. The ovary is superior or half inferior and consists of 3 or 4, rarely 5, fused carpels . The walls of the carpels are incomplete so that the ovary is unilocular in its upper part. The placentation is parietal . The ovules are attached to T-shaped placentas in Parnassia , and directly to the ovary wall in Lepuropetalon . The style is absent or very short. The stigmas are decurrent along

520-434: Is widely cultivated . About 10 species are known in cultivation, all as ornamentals . Parnassiaceae are rhizomatous perennial herbs ( Parnassia ) or winter annuals without a rhizome ( Lepuropetalon ). The youngest part of the stem has three collateral vascular bundles . On the stems, leaves, and flowers, the epidermis has sacs filled with tannin . The leaves are alternate or subopposite , without stipules , and

560-607: The Shorter Oxford English Dictionary defines "herb" as: The same dictionary defines "herbaceous" as: Botanical sources differ from each other on the definition of "herb". For instance, the Hunt Institute for Botanical Documentation includes the condition "when persisting over more than one growing season, the parts of the shoot dying back seasonally". Some orchids, such as species of Phalaenopsis , are described in some sources (including

600-470: The Bering Land Bridge facilitating plant migration. The family and type genus name are derived from the two Latin words saxum (rock), and frango (to break), but the exact origin is unknown, although surmised to refer to either growing in crevices in rocks or medicinal use for kidney stones . Primarily Northern hemisphere temperate and arctic regions, and also tropical montane, including

640-471: The commissures of the ovary and sometimes extended above, to form false styles called stylodia . The stigmatic areas are dry. The megagametophyte is of the ''Polygonum'' type . The fruit is an erect, membranous capsule , which opens at the apex only. The seeds are small, light, and numerous. Parnassias are often grown as curiosities for their unique and prominent staminodes . Further examination reveals additional oddities. The lowest leaves on

680-480: The commissures , the seams where the carpels that compose the ovary are joined together. Such commissural stigmas have been discovered in Celastraceae , but as late as 1972, they were known only from Parnassiaceae and from the basal eudicot family Papaveraceae . Lepuropetalon shares with Parnassia the pseudosessile leaves and the commissural stigmas. It also dumps its pollen on the ovary, but without

720-511: The 15 subfamilies that he recognized in Saxifragaceae . Others thought that they were closely related. One of these was Steven Spongberg , who did a detailed study of Lepuropetalon and placed it in Saxifragaceae in the same subfamily with Parnassia . Most authors have followed Engler or Spongberg in their treatment of these two genera, but often with considerable doubt. Several other possible relationships have been proposed. In 2001,

760-923: The Americas, Europe, North Africa (including montane Ethiopia) and temperate and subtropical Asia to Luzon and New Guinea. In the Americas it extends south to central Mexico and the Andes to Tierra del Fuego . Centres of diversity are western N America, East Asia and the Himalayas. The largest concentration of genera are in the Pacific North West. Some Saxifraga and Chrysosplenium are circumboreal . Others have disjunct distributions between E Asia and N America, while other taxa have separate narrow distributions in southern S America. Some species are found in wet woodlands, swamplike conditions and wet cliff edges. Herbaceous plant The fourth edition of

800-826: The Saxifragaceae alliance, while Penthoroideae and Tetracarpaeoideae are closely related within the core Saxifragales as shown in the cladogram . The remaining subfamilies are all transferred to more distant orders within the rosid and asterid clades. Peridiscaceae (4) Paeonia (Paeoniaceae) Liquidambar (Altingiaceae) Hamamelidaceae (27) Cercidiphyllum (Cercidiphyllaceae) Daphniphyllum (Daphniphyllaceae) Crassulaceae (34) Aphanopetalum (Aphanopetalaceae) Tetracarpaea (Tetracarpaeaceae) Penthorum (Penthoraceae) Haloragaceae s.s. (8) Iteaceae (including Pterostemonaceae ) (2) Ribes (Grossulariaceae) Saxifragaceae s.s. (33) Numerous attempts have been made to subdivide Saxifragoideae (Saxifragaceae s.s. ). These have included dividing

840-404: The analysis of annual growth rings in the secondary root xylem . Herbaceous plants do not produce perennializing above-ground structures using lignin , which is a complex phenolic polymer deposited in the secondary cell wall of all vascular plants. The development of lignin during vascular plant evolution provided mechanical strength, rigidity, and hydrophobicity to secondary cell walls creating

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880-928: The authoritative Plants of the World Online ) as "herbs" but with "leaves persistent or sometimes deciduous". In the glossary of Flora of the Sydney Region , Roger Charles Carolin defines "herb" as a "plant that does not produce a woody stem", and the adjective "herbaceous" as meaning "herb-like, referring to parts of the plant that are green and soft in texture". Herbaceous plants include graminoids , forbs , and ferns . Forbs are generally defined as herbaceous broad-leafed plants, while graminoids are plants with grass-like appearance including true grasses , sedges, and rushes. Herbaceous plants most often are low-growing plants, different from woody plants like trees and shrubs , tending to have soft green stems that lack lignification and their above-ground growth

920-517: The circumscription has been considerably reduced, with many of the subfamilies being either elevated to separate families, or placed as components of other families, often quite distant. For instance subfamily Parnassioideae was raised to the level of family Parnassiaceae , and eventually a subfamily of Celastraceae (order Celastrales ). Similarly the Hydrangoideae is now the family Hydrangeaceae (order Cornales ). The reduced Saxifragaceae

960-453: The cladogram: Saxifraga Leptarrhena Saniculiphyllum Boykinia Astilbe Heuchera Cascadia Darmera Peltoboykinia Micranthes Saxifragaceae s.s. has about 33–35 genera and about 640 species. About half of the genera (18 of 33) are monotypic , but Saxifraga has about 400 species, and has generally been divided into sections. The crown group of Saxifragaceae diversified at about 38  Mya (Mid–Late Eocene ), with

1000-755: The elaborate dance of the stamens. Unlike Parnassia , however, its staminodes are small and lack glands. The genus Parnassia was named by Linnaeus in 1753 for Mount Parnassus in Greece . In 1821, Samuel Frederick Gray put Parnassia in its own family, Parnassiaceae. In that same year, Stephen Elliott gave Lepuropetalon its name and published a description of it. The name is from two Greek words, lepyron , "husk, rind, or shell", and petalon , "leaf or petal". In 1930, botanist Adolf Engler published descriptions of Lepuropetalon and Parnassia with detailed illustrations. He did not consider them to be closely related and placed each in its own subfamily among

1040-465: The end of a peduncle that has few or no leaves. The flowers are perfect and slightly zygomorphic . The five sepals are shortly connate at their bases, and persistent through maturity of the fruit. The petals are either absent, or five and free from each other. In Parnassia , the petals are showy and white or cream, with conspicuous veins that are usually green or gray. The margins are entire , toothed , or fimbriate . In Lepuropetalon ,

1080-707: The end of the growing season, but parts of the plant survive under or close to the ground from season to season (for biennials, until the next growing season, when they grow and flower again, then die). New growth can also develop from living tissues remaining on or under the ground, including roots , a caudex (a thickened portion of the stem at ground level) or various types of underground stems , such as bulbs , corms , stolons , rhizomes and tubers . Examples of herbaceous biennials include carrot , parsnip and common ragwort ; herbaceous perennials include potato , peony , hosta , mint , most ferns and most grasses . Parnassiaceae Parnassiaceae Gray were

1120-402: The evolution of angiosperm lineage, located in an ancestral "Saxifragalean stock". Historically the Saxifragaceae have included many very morphologically disparate taxa in systems based on morphology alone, and has been very difficult to classify and characterize phenotypically . Consequently many different classifications have been published, differing considerably in both the relationship of

1160-433: The family by the placentation of the ovules, as either parietal (e.g. Heuchera ) or axile (e.g. Saxifraga ). None of these has been supported by molecular data. Molecular data indicate that the family can be considered as a number of informal clades , with two main lineages, saxifragoids and heucheroids and further subdivision of heucheroids into nine subclades or groups: The clades and subclades are related as shown in

1200-441: The family to other angiosperms, and its internal structure, for instance the systems of Cronquist (1981), Dahlgren (1983), Engler (1890), Hutchinson (1973), Schulze-Menz (1964), Takhtajan (1980) and Thorne (1992) ( for a history, see Morgan & Soltis (1993) . In its broadest circumscription , it included 17 subfamilies. This construction is referred to as Saxifragaceae sensu lato ( s.l. ). Within those subfamilies,

1240-609: The genus Musa , to which the banana belongs. Some relatively fast-growing herbaceous plants (especially annuals) are pioneers , or early-successional species. Others form the main vegetation of many stable habitats, occurring for example in the ground layer of forests , or in naturally open habitats such as meadow , salt marsh or desert . Some habitats, like grasslands and prairies and savannas , are dominated by herbaceous plants along with aquatic environments like ponds , streams and lakes . The age of some herbaceous perennial plants can be determined by herbchronology ,

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1280-430: The large majority of genera (30) were located within subfamily Saxifragoideae, the core group, with all but two of the remainder only having 1-3 genera. The circumscription of the family has changed considerably in recent years, in large part due to molecular phylogenetic work showing the family s.l. to be polyphyletic , and probably represents the most extreme example, with at least 10 evolutionary lines. Consequently

1320-543: The margins are entire . The leaf blade is wide compared to its length and the secondary venation is subpalmate . In Parnassia , the leaves are crowded into a basal rosette with a few cauline leaves above. The leaves are all cauline in Lepuropetalon . In both genera, the lower cauline leaves are pseudosessile , which means that the petioles are adnate to the stems. The upper cauline leaves, if present, are truly sessile . The inflorescence consists of one, or rarely two, flowers that face upward and are at

1360-517: The more dew it produces, so a short cut of the herbs necessitates watering. For example, if you frequently and shortly cut the grass without watering in an arid zone, then desertification occurs. Most herbaceous plants have a perennial (85%) life cycle but some are annual (15%) or biennial (<1%). Annual plants die completely at the end of the growing season or when they have flowered and fruited, and then new plants grow from seed. Herbaceous perennial and biennial plants may have stems that die at

1400-472: The north temperate zone . There are at least 70 species. Sixty-three species occur in China and 49 of these occur nowhere else. A second area of diversity for Parnassia is North America and about 9 species occur there. Parnassia palustris is the most well known and widely distributed species. It ranges through most of northern Eurasia , Canada , and the western United States . Parnassia palustris

1440-414: The ovary to the outside of the flower. Another stamen then repeats this process. It takes about one day for a stamen to complete its motions, and the order in which they do so varies from one flower to another. The area that is receptive to pollen, the stigmatic area , is not confined to the apex of the ovary or mounted on a style as in most flowers, but extends in bands down the sides of the ovary along

1480-439: The petals are rudimentary or absent. In both genera, the five stamens are free from each other. They are placed opposite the sepals and therefore alternate with the petals. The anthers open in sequence above the gynoecium (see next section). The five staminodes are free and placed opposite the petals. They mature after the stamens. Each consists of a nectariferous pad with filamentous rays arising from its edge. Each ray

1520-823: The species are in the type genus Saxifraga . The family is predominantly distributed in the northern hemisphere, but also in the Andes in South America. Species are herbaceous perennials (rarely annual or biennial ), sometimes succulent or xerophytic , often with perennating rhizomes . The leaves are usually basally aggregated in alternate rosettes, sometimes on inflorescence stems. They are usually simple, rarely pinnately or palmately compound. Their margins may be entire, deeply lobed, cleft, crenate or dentate and petiolate with stipules. The inflorescences are bracteate racemes or cymes. The flowers are hermaphroditic (bisexual), rarely unisexual ( androdioecious ), actinomorphic (rarely zygomorphic ). The perianth

1560-407: The stem appear to be sessile , but in fact the petiole is adnate to the stem and embedded in it. The conductive vessels that enervate the leaf depart from those of the stem far below where the leaf is attached. As soon as the flower opens, the stamens begin to elongate. One of them bends inward, opens the thecae of its anther , and dumps its pollen on the ovary . It then bends away from

1600-593: The two main lineages diversifying arising at about 30 Mya (Late Miocene/Early Oligocene ). The present day heucheroid diversity dates later than the Miocene ( see sublabels in Cladogram II ). Ancestral Saxafragaceae emerged in either East Asia or Western North America, with subsequent dispersal West to Europe and south to South America. From the Eocene to the late Miocene these ancestral land masses were joined by

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