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Encyclopedia Britannica - Main :: SAR-SCY |
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SCROPHULARIACEAE , in botany, a natural order of seed-plants belonging to the sympetalous section of Dicotyledons, and a member of the series Tubiflorae. It is a cosmopolitan order containing about 18o genera with about 2000 species; the majority occur in temperate regions, the numbers diminishing rapidly towards the tropics and colder regions. About 30% of the species are annual herbs, such as eyebright (Euphrasia officinalis), cow-wheat (Melampyrum), and species of Veronica`Fio. 1.Foxglove (Digitalis purpurea). 1, Corolla cut open showing the showing the thick axial four stamens, rather more placenta
than Z nat. size small seeds. 2, Unripe fruit cut lengthwise, 3, Ripe capsule split open. more than 6o% are biennial or generally perennial herbs and undershrubs, such as species of Veronica, mullein (Verbascum), foxglove (Digitalis; fig. 1), &c., while shrubs and trees are rare; Paulownia, a native of the mountains of Japan, a tree with large leaves and handsome panicles of violet flowers
The stem is sometimes prostrate and creeping, as in ivy-leaved toad-flax (Linaria Cymbalaria) and some of the native British Veronicas, but generally erect as in foxglove, figwort, mullein, &c.; a few are climbers as Rhodochiton and Maurandia. The South African genera Hyobanche and Harveya are parasites almost devoid of chlorophyll with scale-like leaves; and many genera are semiparasitic, having green leaves, but attaching themselves by root-suckers to roots of grass, &c., from which they derive part of their nourishment; such are Euphrasia, Rhinanthus, Pedicularis, &c. A few genera are aquatic, e.g. Ambulia (old world tropics), and have much Scrophulariaceae are closely allied to Solanaceae (q.v.), from which divided submerged leaves and entire aerial leaves. The leaf-arrange- they are distinguished by the median position of the carpels, and ment varies; the leaves are alternate as in Verbascum, or the lower generally by the zygomorphic flower; Verbascum and its allies, in leaves are opposite and the upper alternate as in Antirrhinum (snap- dragon ), or all are opposite (Mimulus), or whorled (some Veronicas). All varieties of leaf-arrangement are found in the one genus Veronica (q.v.), in some New Zealand species of which the leaves are small and appressed to the stem. The flowers
placenta
which the flower approaches regularity, form a connecting link. b, Veronica. c, Verbascum. When a terminal flower is present it becomes regular as in toad-flax, where radial symmetry is produced by development of a spur to each petalsuch flowers are termed peloric; all the flowers in a spike are sometimes peloric. In Euphrasia and many species of Veronica the posterior sepal is suppressed, and in Calceolaria the anterior petals are completely united. The form of the corolla shows great variety, depending on the length and breadth of the tubewhich in Veronica is almost obsolete, while in foxglove it is large and almost bell-shapedand the development of the limbs, which are spreading in Veronica, small and almost erect in figwort, or form a pair of closed lips as in Linaria and Antirrhinum. In Linaria the anterior petal is spurred; in Calceolaria a very short tube is succeeded by a two-lipped limb, a smaller upper lip representing the two posterior petals and a larger, often very large, lower lip representing the three anterior petals. In Verbascum the five segments are almost equal, forming a nearly regular corolla; in Veronica the two posterior petals have united and the corolla is four-lobed. The approach to regularity in the corolla in Verbascum is associated with the presence of five fertile stamens, but the three posterior are generally larger than the two anterior. In Veronica, Calceolaria and other genera only two stamens are present. The anthers generally open introrsely by a longitudinal slit; their form shows great variety. These differences in the form of the corolla, the position and length of the stamens and the form of the anthers, are associated with their pollination by insects which probe the flower for honey, which is secreted by a disk surrounding the base of the ovary or by special
nectar
insect
The fruit is generally a capsule surrounded at the base, or some-times as in yellow-rattle (Rhinanthus) enveloped in the persistent calyx; it opens by two or four valves, or, as in Antirrhinum, by pores. Occasionally it is a berry
The order is divided into tribes by characters derived from the number of fertile stamens present and the form of the corolla. It is well represented in Britain by 13 genera, viz. Verbascum (mullein), Linaria (toad-flax), Antirrhinum (snapdragon), Scrophularia (fig-wort), Limosellaa small creeping annual found on edges of ponds, Siblhorpia, a small herb with creeping thread -like stems, Digitalis (foxglove), Veronica (speedwell), Bartsia, Euphrasia (eyebright), Rhinanthus (yellow-rattle), Pedicularis (louse-wort) and Melampyrum (cow-wheat). An American species of Mimulus (M. Langsdorfii) has become naturalized by river-sides in many places. Several genera are well known in gardens; such are Calceolaria, an important genus in temperate South America, Collinsia, Pentstemon and Mimulus (musk), also American genera.An anatomical, distinction is found in the arrangement of the wood
SCRUB-BIRD, the name of an Australian genus, one of the most curious ornithological types of the many furnished by that country. The first examples were procured between Perth and Augusta in West Australia, and were described by J. Gould in the Zoological Society's Proceedings for 1844 (pp. I, 2) as forming a new genus and species under the name of Atrichia clamosa, the great peculiarity observed by that naturalist being the absence of any bristles around the gape, in which respect alone it seemed to differ from the already known genus Sphenura. Later, however; it was given its modern name Atrichornis clamosa, and on account of the discovery of its peculiar sternum (made by A. Newton) it was removed from Oscine division of the Passeres, and the family Atrichornithidae in the sub-oscine division of Passeres was made for the genus, the nearest ally West-Australian Scrub-bird (Atrichornis clamosa). being the lyre-bird (q.v.), now placed in the family Menuridae. Both the known species of scrub-bird are about the size of a small thrushA. clamosa being the larger of the two. This species is brown above, each feather barred with a darker shade; the throat and belly are reddish white, and there is a large black patch on the breast; while the flanks are brown and the lower tail-coverts rufous. A. rufescens of New South Wales has the white and black of the fore-parts replaced by brown, barred much as is the upper plumage. Both species inhabit the thickest " scrub " or brushwood forest; but little has been ascertained as to their mode of life except that the males are noisy, imitative of the notes of other birds, and given to violent gesticulations. The nest and eggs seem never to have been found, and indeed no example of the female of either species is known to have been procured, whence that sex may be inferred to escape observation by its inconspicuous appearance and retiring habits. (A. N.) End of Article: SCROPHULARIACEAE If you wish, you can link directly to this article.
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