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SAXIFRAGACEAE
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SAXIFRAGACEAE , in. See also:botany, a small natural See also:order of See also:Dicotyledons belonging to the sub-class Polypetalae and containing 27 genera with about 350 See also:species distributed through the See also:Arctic and See also:north temperate See also:zone, often alpine. It is repre- sented in See also:Britain by its largest genus See also:Saxifrage (q.v.), Chrysosplenium (See also:golden saxifrage) and Parnassia (grass of See also:Parnassus). The See also:plants are herbs, generally with scattered exstipulate leaves with a broad See also:leaf-See also:base. , The small See also:flowers are generally arranged in cymose inflorescences and are bisexual, See also:regular and hypogynous, y' perigynous or more frequently more (~' or less epigynous, this variation in ():.: ~; the relative position of the ovary occurring in one and the same genus Saxifraga (fig. 1). The flowers are FIG. 2.—See also:Diagram of a 5-merous, more rarely 4-merous, saxifrage (Saxifraga tridachaving 5 (or 4) sepals, 5 (or 4) See also:free tylites). The calyx and petals, two 5- or 4-merous whorls of corolla each consist of five free stamens which are obdiploste parts, tl ere are ten stamens i.e. those of the See also:outer whorl of two two carpels. e and a See also:pistil monous, of are opposite to the petals, and two carpels (see fig. 2). The carpels are sometimes free, more generally See also:united at the base, or sometimes completely joined to See also:form a one- or two-chambered ovary with two free styles. The See also:fruit is a many-seeded See also:capsule. More than See also:half the species (20o) are contained in the genus Saxifrage (q.v.). Chrysosplenium, with 39 species, two of which are See also:British, three valves, by means of which 2 3 a s 6 7 8 the See also:compass is rendered See also:chromatic, and which See also:act as in other See also:valve See also:instruments, lowering the See also:pitch of the See also:instrument when depressed, respectively r See also:tone, a semitone and 12 tones; and further, when used in See also:combination, 2 tones, 21 tones and 3 tones . The Flugelhorns, the See also:euphonium, the bornbardon and the tubas are sometimes erroneously classed as saxhorns. The difference between saxhorns and bombardons or tubas consists in the calibre of the See also:bore, which in the latter is sufficiently wide in proportion to the length to produce the fundamental See also:note of the See also:harmonic See also:series an See also:octave below the lowest note of the saxhorns. The consequence of this structural difference is important, for whereas the See also:tube of the tubas is theoretically of the same length as an open See also:organ See also:pipe of the same pitch, the saxhorns require a tube twice that length to produce the same See also:scale. For instance, a euphonium See also:sounding 8 ft. C only needs a tube 8 ft. See also:long, whereas the corresponding See also:bass See also:saxhorn requires one 16 ft. long. In See also:Germany these structural See also:differences have given rise to a See also:classification of See also:brass See also:wind instruments as whole or half instruments (Ganze or Halbe),' according to whether the whole or only the half of the length of tubing is of See also:practical use. The members of the saxhorn See also:family are the small saxhorn in Eb, the See also:soprano in Bb, the See also:alto in Eb, the See also:tenor in Bb, the bass in Bb (an octave See also:lower), the See also:low bass in Eb, the contra-bass in Bb, three octaves below the soprano. All the saxhorns are treated as transposing instruments .2 A similar family, constructed with rotary valves and conical tubes of larger calibre than the saxhorns, but having the same harmonic scale, is known in Germany as Flugelhorn. (K. S.) has a very similar See also:distribution. The North See also:American genus Heuchera has sometimes apetalous flowers. Astilbe has 6 species in temperate See also:Asia and north-eastern North See also:America; A. japonica is commonly grown in the See also:spring as a pot-plant, and often misnamed Spiraea. The order is frequently much extended to include other See also:groups of genera differing in See also:habit and more or less in See also:general conformation from those to which the order is here confined, and which are then regarded as forming one of several tribes. Among these is the order Ribesiaceae, comprising one single genus Ribes, to which belong the See also:gooseberry (R. Grossularia) and currants of gardens. These are shrubs with racemes of flowers which have only one whorl of stamens (isostemonous), an inferior unilocular ovary with two parietal placentas, and fruit a See also:berry. Another is the Hydrangeaceae, to which belong See also:Hydrangea (q.v.), Deutzia and Philadelphus, all well-known See also:garden plants; P. coronarius is the so-called Syringa or See also:mock-See also:orange. They are shrubs or trees with See also:simple generally opposite leaves, 5-merous flowers with epigynous stamens and a 3- to 5-locular ovary. Escallonia, which represents a small See also:group of genera with leathery gland-dotted leaves, is also often included. Additional information and CommentsThere are no comments yet for this article.
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