Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/450

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largeft common fedum. 5. The broad leaved fedum with large white flowers. 6. The large mountain-y^am with

. dentated leaves. 7. The large mountim-fedum with whole leaves. 8. The woolly mountzm- houfeleek. 9. The fmaller woolly mountain-yt-rfam. 10. The large Alpine rofe-fedum with fnarp pointed leaves. 11. The middle fized Alpine rofe- fedttm with red prickles. 12. The greenifh hairy Alpine lofe-fedum. 13. 'l'he long leaved hairy Alpine fedum. 14. The hairy Alpine fedum with the diflc of the flower green, and the corona purple. 1 5. The fmaller white flowered cy- iindric leaved fedum, 16. The larger cyiindric leaved white flowered fcd/wi. 17. The fmall cyiindric leaved fedum, call- ed the lejj'er houfeletk of the Hi ops. 18. The fmaller cyiin- dric leaved yellow flowered fedum. 19. The fmall round leaved fedum. 20. The fharp pointed leaved fmall yellow fedum. 21. The hSesfeJum with broad and thick ftalks. 22. The lefl'er yellow fedum with inflated ftalks. 23. The deep yellow flowered long leaved fedum. 24. The red flowered field -fedum. 25. The little yellow flowered fharp taftcd fedum. 26. The fmalleft yellow flowered fedum, in- fipid to the tafte. 27. The little infipid white flowered fe- dum, 28. The pale flowered Alpine fedum. 29. The Alpine fedum with large red flowers. 30. The hairy purple marfh- fedum. 31. The white flowered echinated, or ftellated fe- dum. 32. The yellow flowered eckinated fedum. 33. 1 he fedum, commonly called cep&a. 34. The purple flowered cepesa. .35. The fmalleft mo\mt:\\n-fedwn with little purple flowers, and ftellated feeds. 36. The coris-leaved Alpine fedum. 37. The ftirubby heath-like African fedum. Thefe are the genuine fpecies of fedum; but beftde thefe, authors have called many other plants by this name, moft of them properly of the faxifrage kind. Toum. Inft. p. 262. The great houfeleek was called by many names among the Greeks, as zoophthalmus, and buphthalmus ; the latter of thefe confound it with one of the corymbiferous plants, and it is not to be known which of two fo different vegetables the authors mean, without examining the virtues they afcribe to it.

There is however another name, by which it is called, which yet more perplexes the fenfe ; this is ambrofia, a word by which we exprefs the botrys, or oak of Jerufalem, a fmall garden plant, but by which they exprefled the lilly, the houfeleek, and feveral other plants.

SEED {Cycl.) — The exterior form, and even the internal ftrudture, of the generality of vegetable feeds, have been fup- pofed by fome fo much alike in the feveral kinds, and of fo little curiofity and beauty in the whole, that they have been little regarded by the curious ; but when nearly examined with the help of microfcopes, they are found to be worthy of a greater attention : thofe which appear moft like to one another, when viewed by the naked eye, often proving as difterent, when thus examined, in their feveral forms and characters, as the difterent genera of any other bodies of the creation. If their external forms carry all this variety and beauty about them, their internal ftructure, when laid open by different feet ions, appears yet more admirable. 1 he feed of the mulk fcabious is amazing in its fhape and ilructure: it refembles in figure an octagonal vafe, with a fcalloped brim; the whole is bell-fafhioned, having ribs or divilions, which run down from the mouth of the vafe, and thence becoming narrower, form the bottom. Between thefe ribs, down to the beginning of the narrow part, it is clear, though not wholly tranfparent, and from thence to the bottom the ribs are hairy. This vafe contains a feed, which is like a peftle ftanding in a mortar. The peftle ftands loole in an octagonal cafe, but the narrownefs of the mouth of this vale hinders the peflle's being drawn out, becaufe its extremity within is rounded, and thicker than any other part of it. From its upper end there arife five fpiculated urifhe, or awns, whofe little thorns are directed upwards, and are thereby prepared to caufe the feed to recede from any thing that might injure it on being touched. The bafon, from which thefe ariihe rife, is of a fine green colour, and they are of an elegant mining brown.

The feed of the angelica is one of the moft fragrant in its fmell in the world. When the outer hufk of this feed is pull- ed oft, the nucleus appears of a brownifh colour, and of an elliptical fhape. By the help of the microfcope we foon difcover what it is that produces this charming fmeli ; this is a fine amber coloured gum, which appears laid la rido-es, difpofed alternately with others of a brownifh colour, longi- tudinally, all over the feed, and on the flat fide there is a white part, which is a fort of theca, which receives a very minute fly 1 us from the pedicle that fupports it. The medicinal feed, commonly known in the /hops under the name of grain of paradife, is one that promifes very little from its external appearance, being only a brown feed ot an irregtdar furface, with many flats and angles, and having an apex like the mouth of a purfe when drawn to- gether with a firing; from this unpromifing afpect, how- ever, there arifes a very wonderful appearance on diflection. In a longitudinal lection we fee firft the edge of the brown cortex, next within that appears a black pitchy fubftance, and within that a very white matter, lodged in a radiated

form : this refembles a fine white fiilt, and Is probably a mixture of a volatile fait, and a farinaceous matter. Its ra- diated difpofition, and extremely pungent tafte, favour alfo this opinion. But there is in tint feed a. yet far more curi- ous particular than thefe ; the center ot every feed is occupied by a fmall piece of perfect camphor: this is, in all refpects, the fame with the common camphor fold in the fhops, and is always of the figure cf a vinegar cruet, having :i round large bottom, and a long and narrow neck. This is invari- ably the appearance in every feed, and that not only in this, but in other feeds of the fame kind.

The feed of the great maple, which we commonly, but im- properly call the fyemnore-tree, confifts of a pod and its wing : two of thefe grow upon a pedicle with the pods to- gether, which makes them refemble the body of an infect with its expanded wings. The wings are finely vafculated, and the pods are winged with a fine white down, refembiing filk : this contains a round compact pellet, covered with a brown membrane, that flicks very clofely to it. When this is pulled off, inftead of difcerning a kernel, as in other feeds, there appears an entire green plant, folded up in a moft furprifing manner. The pedicle of this is about two eights of an inch long, and its feminal leaves of about fix eighths each: between thefe the germina of the next pair of leaves are plainly vifible to the naked eye, but with a mi- crofcope they are feen with the greateft beauty and per- fection. See Tab. of Microfcopical Objects, CUs 2. Thefe, and a number of fuch other beauties in this part of the creation, are defcribed at large by Dr. Parfons in his work, entitled A M'tcrofspk Theatre of Seeds, to which wc refer for the reft. Philof. T'ranf. N° 474. p. 187. The increafe of the feeds of plants is furprifing. The upright mallow, for inftancc, has been computed to produce 2QOG00 feeds from one. See Philof. Tranf. N J 4&8. lect. 4. Moft kinds of feeds fhould be prepared for a microfcopical examination, by fteeping them in warm water till their coats are feparated, and their feminal leaves may be opened with- out laceration. But Jeeds, while dry, and without any pre- paration, are of an almoft infinite variety of fhape, and afford a number of plcafing objects for the microfcope. The feeds of ftrawberries rife out of the pulp of the fruit, and appear themfelves like ftrawberries. The feeds of the feveral forts of poppies refemble kidneys in fhape, but have a number of furrows and ridges on their furfaces, very curi- oufly difpofed with regular fides and angles. From thefe feeds there may alfo be commonly fhaken a duff, which looks very pretty before the microfcope, having nearly the fame appearance with the furface of the feeds, but having the advantage of being tranfparent. This duft is compofed of the fine membranes which have Iain between the feeds + and which by the preffure of the feeds againft them have re- ceived the very marks of every part of the feeds. The feeds of the lefl'er moonwort, of tobacco, chervil, let- tuce, thyme, parflcy, and a multitude of others, afford alfo a very pleafing entertainment. The antients imagined, that the ferns and capillary plants produced no feeds, and their miftake could never have been rectified hy the naked eye ; but the microfcope has difcovered, chat all the feveral forts of fern, harts-tongue, maiden-hair, and the like, are fo far from being barren in this refpect, that they are really amaz- ingly fruitful. The feed veffels of thefe plants are placed on the back part of their leaves, and the duft which flies off from them in fuch great quantities, when we handle them, is no other than their feeds. The feed veffels appear to the naked eye like brown or black fcurfF, on the backiide of the leaf, but when viewed by the microfcope, they refem- ble little circular tubes, divided into feveral cells, and con- taining a multitude of y*w/r. When the feeds are ripe, the veflels fly open with a faring, and throw them out every way in form of duft. Baker's Microfcope, p. 250. Mr. Lewenhoek obfetves, that the meally fubftance in the feeds of beans, peafe, wheat, bailey, and other kinds of grain, and the generality of other large flrds, is always en- clofed in certain fmall membranes, reprefenting fo many little bags or facks. On oblerving thefe membranes more nicely, they were found to be all full of fmall holes, through which he could fee the light, and which he judged to be no other than the remains of truncated veflels, which had been torn off in feparating the part, and which ferve to compote a great part of the membranes ; and it is probable, that each minute particle of the farina of thefe feeds is nourifhed by the veflels, of which we, in this view, fee the truncated ends. Thefe veflels are more eafily fecn in beans and peafe, than in the grains of wheat, cjV. whale membranes are fo extremely thin and brittle, that they are deftroyed with the leaft touch. In wheat, however, there is this Angularity, that one globule of the farina being broken, is always fecn to be compofed of many more, or that many much fmaller globules'were contained in every one of thefe larger ones. The membranes in barley, in which the fmall globules of fa r rinaceous matter are contained, are much thicker anil ftronger than in wheat, but much lefs ftrong than in the leguminous feeds. See Tab. of Microfcopical Objects,

Clafs 2.

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