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ferous ones occupying the centre, and the pistilliferous the circumference. In both the perianth has four lobes; the anthers are usually eight, arranged in a circle round a central column (fig. 8); the pistil is single, with a radiately-lobed stigma and an ovary adherent to the perianth, and imperfectly divided into compartments containing a great number of ovules (fig. 9). The sucker, or cone of attachment, is slowly developed and perforates the bark of the C'istus; it possesses numerous spiral vessels, but no distinct vascular connexion with the stock occurs (figs. 6-7 This plant is the inrélcwns of Dioscorides, in whose time the black juice, which contains gallic acid, was used, as it still is, as a styptic and astringent.

As an example of the polystomal parasites Lath'roea Squa— Imaria, a familiar British species, is figured (Plate 0., figs. 1—4). This is to be found in early spring, on a diligent search, half hidden (whence its name) at the foot of hazels, elms, and other trees, in damp shady places. When fresh, the whole plant is white with a pink or purple tinge, and semi-transparent, but becomes perfectly black when driedfi" It possesses a subterranean definite branched rhizome, from which the flower-branches arise, and which is clothed with thick tooth-like scales, from the axils of some of which slender rootlets are given off._ The observations of Mr. Bowman in 1829 first showed that upon these rootlets were borne the absorbent tubercles (fig. 2). Careful washing away the soil will show these attached to the rootlets of the supporting plant, and a section through both (fig. 3), displays a perforating cone, penetrating the bark at least, and, as I am informed by Mr. Stratton, actually pushing its way into the very wood. The singular fleshy scales of this plant, from which it has received its name of Toothwort, are, like the whole plant, very brittle ; they are of course homologous with leaves, and are remarkable for possessing in their interior numerous irregular cavities, on the walls of which are arranged stalked gland-like bodies (fig. 4). The allied genus, Clandestina, possesses similar organs, the objects of which are not known.

Of the genus Orobanche, which we may take to illustrate the polyrrhizal parasites, there have been described seventy or eighty species all having a strong family resemblance; about ten of' these are inhabitants of England, but their distinctions are illdefined. The common 0. minor is a pest of clover-fields in some parts, being doubtless often sown with the crop, and doing con

' Immersion in spirit has the same effect, and the spirit becomes of a fine purple colour. Monotropa Hypopitys behaves in the same way, and Dr. Lindberg suggests that the colouring matter may be indigo. See his paper in “ Journal of Botany,” 1873, p. 179.

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siderable damage. Still more harmful in some parts of France is the O. ramosa, parasitic on hemp chiefly, and the subject of ' the illustration Plate XCIX., figs. 5—9. Their habits were known to antiquity, as the name Orobcmche (é'xyxew, to strangle), which dates from Dioscorides, denotes. Turner, the first English botanical author, describes in 1562 his discovery of the clover speciesthus :—He noticed an Orobanche by the side of a “common claver or medow trifoly which was all weathered, and when I had dragged up the root of the trifoly to see what shulde be the cause that all other clavers or trifolies about were green and freshe that that trifoly should be dede, I found the rootes of orobanche fast clasped about tlie rootes of the claver, which as I did plainly perceive did draw out all the natural moisture from the herbe that it should have lived withall and so killed it” (Herball, pt. ii. f. 71). The aspect of the various species is very similar; a spike of rather showy flowers on a brown erect stem, with scattered scales more numerous at the base, which is swollen and possesses a single large sucker, attached usually laterally to the extremity of a rootlet of the victim. Around this, from the bulbous base of the axis arise numerous thickened fibres, which penetrate the soil and probably serve chiefly as holdfasts. The germination of the minute seeds of O. 'ramosa, (fig. 7) has been investigated by Vaucher and Caspary. This occurs in the soil, but an adherence to the extremity of a ' young rootlet of the hemp is almost immediately efi'ected. At first the little parasite puts out a number of rootlets (fig. 8), but before long it forms a true union with the stock. The vessels of the hemp are stated to pass actually into the young Orobcmche, as represented in fig. 9, and in the adult state in fig. 6. Besides Lathraza. and Orobomche, there are about twenty other genera in the order Orobtmchacecc, containing over 130' species, the whole of which are parasitic.

The leafy or chlorophyllous parasites may perhaps form the subject of another communication.

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" HE unprecedented development, during late years, of the science of astronomy as regards its extent, must necessarily in the end lead to a subdivision of labour. In the days .of the old refractor, the earlier achromatic, and the metallic speculum, the ordinary subjects of observation could easily be examined within a moderate time; before we had penetrated so far into the temple, the eye could readily embrace its more accessible and obvious glories. But the case is now greatly altered by the increased facilities of study. The achromatic has been at once enlarging in size and diminishing in price; and its beautiful and less expensive substitute, the silvered . reflector, has been gradually winning its way, as it well de-l serves : and not only are observers thus greatly multiplied by the removal of a very serious pecuniary restriction, but the objects of observation are almost indefinitely increased, and work is'found to abound even in a- greater proportion than 'corresponds with the improved means of accomplishing it. It is therefore advisable that those who are disposed to cultivate this fascinating study should mark out for themselves some definite line of enquiry, and such a line as may conduce in its prosecution not merely to individual amusement, but to the advancement of the science. If, indeed, our intention goes no further than merely to see for ourselves, or to show to our friends, in a general view, how the heavens declare the glory of Gen, we may be well satisfied with simply gazing at such objects as the season of the year may present. But if we really intend to ‘leave our footprint on the sands of time,’ we had better arrange our operations on some definite system. Nights may be wasted; energy misapplied; fine weather turned to little account, in merely looking about us, when we might have been doing work of some value. Numerous lines of enquiry might be specified, that promise ;a reward to the diligent investigator; but at present our remarks will be limited to the study of the lunar surface, more especially

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