OCR Text |
Show 6 'Ihe Hijlory of P L A N T S. there are no fpaces between~ and they form, by this means, irregul~rly pentangular or hexangular figures. Thefe are large, and their cavities filled up w1~h very ~umerou s, thin and beautiful lamellre: there are often fixty, or more of thefe m a c::tvJty. This fpecies is found in the Mediterranean, growing often deep under water, on the rocks near the {hare. 5· Ajlercet;T- gyris crajfijjimis planis. The thick and flat partitioned Ajlercea. This is by much the moft fingular of all the fpecies of Afterrea; in all the ot~ers the ftars make up the greateft part of the furface, whence we .have named them f10m thofe as the mofl: obvious marks of difl:inetion; in this, the gyn take up the far greater part, 'whence we name it from them. T.his grows from an extreamly large an~ broad bafe which (eems indeed a kind of core to 1t; the matter of the furface often makmg only a {b~lly covering over it. It is ufually met with of the bi&nefs of a hen's egg, or thereabout, but it fometimes grows much lar~er. Its ~gure. 1s rounded, and very co~ve:c. The gyri are extreamly hard, and as white and fohd as Ivory nea: the furface; w1thm they are full of holes. They do not rife into rounded furfaces, as m ma1:y of the other fpecies, but are flat, and, in general, of the breadth of a .large {haw; 111 fame plac~s, where they coalefce, they are much more : they are d1fp.e:fed ov.er the fur£1.ce m irregular and ftrange forms ; but they every-where ma~e cav1t1.es, whtch are. fmall, and of a roundiih, or irregularly-oval figure; . thefe are radJated w1th lamellre, 111 the fame manner as thofe of the rttfl:. They are thin, fmall, and not placed very near one another; and it is fin gular in this fpecies, that t~e ftars are deep _funk in from the furface, fo that the gyri only, at a little difl:ance, are feen; and thefe g1ve the whole much of the appearance of that kind of mulhroom which we call the Morel. This is lefs frequent than the others, and is oftener found in the Eafl: Indies than any where elfe. Boerhaave, fi·om its external refemblance .to the boletus, or morel_, calls it Fungus marinus lapideus boletum Tournefortianum referens: he adds, Colore cmereo. But the true colour of the fpecies is pure white. . . Thefe are all the difl:intt fpecies of the Afierrea yet known; the vanet1es of them are almofi innumerable, but all may be referred to one or other of thefe. _ S U B M A R I J.V E S. C!afs the Fir.ft. Genus the Third. MADRE P 0 R A. M AD R E P 0 R A is a genus of Submarines, of a fiony bardnefs, but fomewhat approaching to the ordinary figure of vegetables in its form. It is compofed of a main fiem, divided and fubdivided into a number of branches, which are full of pores, or holes, running from the circumference to the center df the branch, and furnifhed with lamellcc, difpofed in a fl:ellar or radiated manner. The furface in fome of the fpecies is fmooth, and the pores larger, and at greater difiances. In others it is il:riated, and the pores are fmaller and clofer. The ftri~ in thefe fpecies are formed of a kind of lamell::e, growing from the furface of the tubules which form the pores. Thefe always il:and out beyond the reft of the furface, and their cavity is frequently intercepted by little tra~fverfe lamellre within, which divide it into cells, in the manner of tbe cavities in the nautili and cornua Ammonis. Many of the Madreporre approach to the nature of coral in their texture : others of them are lefs hard. · I. Madrepora glabra poris magnis. The finooth Madtepora with large pores. This is the plant generally known under the name of White Coral. It is a very beautiful fpecies of Madrepora. It grows to eighteen or twenty inches in height, and freque~tly .extends it's ramifications fo wide every way, as to be in the whole nearly as much m diameter. It grows up with a fingle fiem, of the thicknefs of a man's thumb, or Tbe Eiflory of P L A N T S. 7 or more: this .is not firait, ~ut t?rtuous, and full of prominent tubules, open at their tops, and forming pores; thts mam fiem foon fends off a number of branches, which again ramify into feveral more, extending themfelves every way, and fending out, at different fpaces, other {hart branches, which feem, indeed, no more than long tubules, or conduits of pores. Befide thefe, the whole plant has it's furface fpangled over with pores, at fmall difl:ances, a quarter of an inch, or more, being left folid between them, fometimes confiderably more. The pores in the larger branches are fuch, as will admit a tare; in the fmaller branches they are lefs, but in all confiderably large. They ftand out a little way from the furface, and have a fmooth edge: within they are radiated with bmellcc, like thofe of the aftercca. The colour of this fpecies is a fine, bright white ; and it's furface between the pores is bdght and glo.lfy. It looks perfeCtly fmooth, till clofely examined; but it is then found to be lightly ftriated, efpecially in the larger parts of the plant. The branches, when broken, {hew a folid texture, except jufi: where the pores run; they are whiter within than on the furface, and the confl:ituent matter feems very like that of red coral. It is found on the rocks, under water, about the ihores of Italy, and in many other places. Tournefort calls it Madrepora vulgaris; C. Ba.uhine, Corallitim album oculatum oilicinarum. 2. Madrepora jlriata poris minoribus frequentioribus. The jlriated Madrepora with more frequent and Jmall pores. This is an extreamly elegant plant. It rifes with a tin gle fiem, of an inch, or · more, in diameter, which foon divides itfelf into a great number of branches; and thefe fend off others, till, from the whole, there is fo rmed a beautifully ramofc figure, of a foot or two in height, and nearly of as much in diameter. The branches are many of them as thick as a man's thumb; they are ufually a little crooked, and all point upwards. The whole plant is ufually of a beautiful white, fome times grcyi{h, and is very brittle, which is owing to its being very porous. The furface is all over covered with little prominences, of the bignefs of half a barley-corn, or thereabout. Thefe are b:oaddl: at the bafe, and fmaller at the point, and are lamellated ve ry finely and beautifully on the outfide. Thefc lamell<E are continued from the fummit of one protuberance to the bafe of another, and, by that means, form the ftriated furface of the whole plant : thefe protuberances are the tubules of the pores: they are all open at top and are beautifully lamellated within, their lamellre, like thofe of the external furface' being extreamly thin and fine. If a branch is broken, it is found to be of an ex~ treamly lax and cavernous texture, and every pore of the furface is feen to be carried down to the center, whe:·e there runs up another cavity, filled with lawtllre, as the refl: are , up to the fummtt of the plant. This is frequent about the ihores of the Eaft Indies, and is fometimes met with about thofe of the Caribbee Hlands; it grows to the rocks, at a little depth under water. 3. Madrepora poris deprejjis. The Madrepora with deprejfed pores. This is a very beautiful fpecies of Madrepora, and very .different in it's firuC!:ure from mofl: of the others; it does not grow to the height that many of them do, but it expands fuHiciently in breadth, and it's branches are not round, but flattiili. It :-ifes with a fingl~ ftem, of a v~ry irr:gular figure, protuberant,. but flattiih; this, at the height o.f an mch or two, d1v1des mto feveral branches, wh1ch ufually extend themfelves honzontally, and are flat, often about an inch in breadth, and not more than a third of an inch in thicknefs: thefe alfo frequently fend off other branches of the fame figure; but fome of thefe, as well as fome of the large ones, approach more to roundnefs than the others. The whole plant often extends to a foot or more horizontally, though not above five inches in height. It's colour is a pure white. It's furface is covered wjth little roundiih depreffions, capable of admitting the head of a moderate pin ; they fiand very clofe to one another, and the inrerfiitial matter between them is granulated : ~mong thefe pores there riie alfo, on different parts of the branches, a vall: number of little protuberances, about an eighth of an inch in length, and nearly as much in diameter, and of a perfectly irregular figure : thefe arc not the tubul es of pores as the pro- |