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The root of tlie orobuiiclie, tigiircJ and dcfcribcil liy t!ic 

 f.imc aiithur, is of a more iliibious nature. In the firft place, 

 it ilof j not belong to the monocotyledinousdivifiou of plants, 

 in which the legitimate bulbous plants are ufually, if not 

 aliv.iys, found. In the next place, it produces on its furface 

 fcattcrcd gems, each fupported by an exterior, caducous lenf ; 

 fomc of whicli gems fpring alfo from the ftem, or afcending 

 caudex. We prefume, therefore, that it may be llited a 

 defccnding caudcx, with germ-bearing leaves, analogous to 

 thofe of trees and (liiubs. It may be proper, however, to 

 remark, that IJernard JutTitu, as we learn from La Marck's 

 " Flore Fran^-oife, Difcours Preliminaire," p. f,^. placed 

 in the royal garden at Trianon, orobanche, lathrsa, and 

 fome others, in the divilion of the monocotyltdinous plants. 

 Anthony JulTieu, on account of their having both a calyx 

 and a corolla, and their evident affinity to other didynamous 

 genera, hjs judjed them to be dicotyledinous. What in- 

 duced his illuHrious uncle to think otherwife we are not 

 told. The parafitic growth of all the fpecies of orobanche 

 renders it diflicult to afcertain in what manner they fpiing 

 from the feed : but the difpofition adopted by fo eminent 

 a botanill, and the defcription of the root given above from 

 Malpighi, fceni to indicate a fomcthing of a monocotyltdi- 

 nous charafter, and afford ground for a conjtfture, that in 

 thefe plants a conneding link between thofe grand natural 

 divifions may be found. 



The root of the common turnip (braffica rapa) which has 

 been called a bulb by many writers, though not by Linnaeus, 

 is nothing more than an intumefcence of the defcending 

 caudex, produced by a luxuriant foil ; and moft generally 

 the elTeci of cultivation, differing from the cultivated carrot 

 (daucus carota), which no one ever thought a bulb, merely 

 in form. Neither of them has any claim to the charaftsr 

 of an hybcrnaculum. 



The articulated, or jointed bulb, confids of lamellae or 

 fcales, linked or chained together ; fuch as are found on 

 tuberous molchatel(adoxa mofchatcllina), the greater tooth- 

 wort (lathra?a fquamata), and bulbiferous coral-root (den- 

 taria bulbifera). The only inllance of this kind of root 

 given by La Marck, is that of white faxifrage (faxifraga 

 granulata), but he thinks it fhould rather be ranked with 

 the tuberous than the bulbous roots. 



Ventenat, in the " Botanic Dictionary, " prefixed to his 

 " Tableau du Rfgne Vegetal," confines the term bulb to 

 thofe which are ilriftly tuuicated or coated, among which, 

 as we have fcen, thofe ftiled folid by Linnsus ought to be 

 placed ; and has ranked with the tubers univerfally fo called, 

 (fueh as thofe of the common potatoc), the globular root 

 of the turnip radilh, (a variety of raphanus fativns), intend- 

 ing, doubtlefs, to include the common turnip ; the fcaly root 

 of the lily ; the knotty root of the common dropwort 

 (fpirxa filipendula) ; the articulated root of tuberus mofcha- 

 tel ; the falcicuhted root of afphodelus hiteus and creticus ; 

 the grumous root, of the garden ranunculus (R. Afiaticus); 

 and the fcrotiform, or didymous root of fevcral fpecies of 

 orchis. We are inclined to think that this able botanilt is 

 ri?ht in feparating all thtfe from the proper bulb ; the 

 effential charatler of which will then depend on its tunicated 

 ftrufture, and the difference of the fpecies will arife from the 

 v.irious thicknefs of the coats, and the proportion of their 

 ■whole fubdarice to that of the defcending caudex : but the 

 remaining ones are fo diffimilarto each other in feveral impor- 

 tant refpefts, that they cannot, with any degree of prccifion, 

 be called by the fame name. 



The true di'Unclion between a bulb and a tuber appears 

 to us to be in their relative fituation with refpeft to the 

 defcending caudex. Tiie bulb cro-.vns the proper root, and 

 4 



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has the caudex interpafed between it and the radicles. The- 

 tuber is fituated mickr the caudex, either on the fame plan 

 with the radicles, as in fome fpecies of orchidcs ; or, Hill 

 lower, when it is evidently an intumefcence of the radicle 

 itfelf, as in the common potatoe. Linnaus, in his praftical 

 works, uniformly calls thofe roots of the orchidere, which 

 anfwer this defcription, bulbs ; folely, it fhould feem, on 

 account of their general appearance ; for they are not men- 

 tioned under any of his four divifions, and do not corrcfpo-nd 

 with either of the definitions quoted above from the " Philo- 

 fophia Botanica," and the " Termini Botanici." That 

 they do not effentially differ from the tuber of the commou 

 potatoe, is evident from the fteps by which, in different fpe- 

 cies, they approach that well known and invaluable efculent. 

 In orchis bifolia, pyramidalis, ulhilata, 5cc. they fpring im- 

 mediately from the caudex along with the proper radicles : 

 ill orchis mafcula, ophrys apifera, &c. they fwell fuddenly 

 fro.m the radicle itfelf at a fmall diilance from its origin: 

 and in ophrys monorchis, the new tuber is fo far from the 

 caudex as to be apparently not different from that of the 

 potatoe. Thefe fcrotiform tubers differ only in number 

 from the palmate, fafcicled, and aggregate tubers of other 

 fpecies, between which, and thofe of common pilewort (Ra- 

 nunculus ficaria), afphodelus luteus, &c. as far as the fub- 

 jedl has been hitherto invcftigated, no certain line of dillinc- 

 tion can be drawn. All the radicles of ophrys nidus avis, 

 birds-neft orchis, are fwoUen into tubers. The rare ophrys 

 Loefelii appears to differ from all the reft of its natural fa- 

 mily, in having a true bulb. A tuber, therefore, is an in- 

 tumefcence of the radicle, as the turiiip, carrct, &c. are of 

 the caudex ; and, like them, may poffibly be, in fome cafes", 

 merely a rtfervoir for the nourilhment of the prefenf ftem, 

 particularly in a droughty feafon. In this light the fingu- 

 lar tubers of fpirsa fihpeiidula are confidered by Dr. Smith. 

 But it is more commonly, and as no aflual obfervations have 

 been made on the roots of filipendula to determine the quef- 

 tion, we are rather inclined to think it always a real hybtrna- 

 culum, having imbedded in its fubftance the rudiments r/f 

 one or more future buds in a lefs advanced ftate than that 

 of the bulb. When the tuber is fmall, and contains only a 

 fingle bud, as in feveial leguminous plants, and perhaps 

 fome graffes, it is called a tubercle. 



Ventenat is probably corred in placing the grumous root 

 of the garden ranunculus under this head. But the fcaly 

 root of the white lily, &c. differs effentially from the tuber 

 in being placed upon the caudex ; as it does from the true 

 coated bulb, in having a loofer texture ; being, in faft, com- 

 pofed of unconnefled fcales, which, by their concave fhape, 

 are fo adapted to each other, as to produce the appearance 

 of a bulb. The fcales of common wood forrel (oxalis aceto^ 

 fella) are of the fame kind, but fmaller, and fomewhat lefs 

 compaa : thofe of tuberous mofchatel have, in a ftill lefs 

 degree, the form of a bulb : and in the bulbiferous coral- 

 wort the refemblance totally vanifhes. They all, we appre- 

 hend, agree in having the rudiment or bud of a future plant 

 fituated at their axils, to proteft which feems their proper 

 ufe ; and if torn off with a fmall part of the caudex, and 

 planted in a fuitable foil, will readily take root. Radical 

 fibres are indeed plentifully thrown out under the fcales of 

 tuberous mofchatel while they are attached to the parent 

 plant ; they are found more fparingly in bulbiferous coral- 

 wort ; and fometimes, as appears from Malpighi's figure, 

 occur in the white lily. Roots of this kind feem to form a 

 conneding link between the true tunicated bulb, and the 

 proper bud or gem of the afcending caudex in trees and 

 fhrubs. The greater toothwort, having no other radicles, 

 IS, we conceive, rather allied to the ophrys nidus avis ; and in 



this 



