The anatomy of plants with an idea of a philosophical history of plants, and several other lectures, read before the royal society / by Nehemjah Grew ...

CHAP. II. Of the Barque, as it appears through a good Microscope.

I NOW proceed to a more particular Description of several Trunks and Branches, as they appear through good Glasses.

1. §. Now the Trunk, or Branch of every Tree, hath Three General Parts to be described; sc. the Barque, the Wood, and the Pith. That likewise of every Herbaceous Plant, hath either the same Three Parts; or else Three Parts Analogous; sc. the Cortical, the Lignous, and the Pithy Parts.

2. §. The Barque consisteth of two Parts, sc. the outmost or Skin, and the Main Body. The Skin is generally composed, in part, of very small Vesicles or Bladders, cluster'd together. That is, originally it is so; but as the Plant grows, the Skin dries, and the said Bladders, do very much shrink up and disappear.

3. §. Amongst these Bladders of the Skin, there are usually inter∣mixed a sort of Lignous Fibres,* 1.1 or Vessels, which run through the length of the Skin; as in Mallow, Nettle, Borage, Thistle, and most Herbs. Which is argued not only from the Toughness of the Skin by means of the said Vessels; but in some Plants, may be plainly seen, as in Teasle. In which▪

the several Fibres, which run by the length of the Stalk, are also con∣joyned by other smaller ones, which stand transversly.

4. §. Whether they are Aer-Vessels, or Sap-Vessels, is dubious. For, on the one hand, because they emit no Sap, or bleed not, and also stand adjacent to the Aer; 'tis probable that they are Aer-Vessels. On the other hand, they may be Sap-Vessels; notwithstanding that they bleed not: Because the non-emission of Sap is not an infallible and concluding argument of an Aer-Vessel. For there are some Plants which bleed not. Which yet are furnished with Sap-Vessels, as certainly as any others which bleed.a 1.2

5. §. The Skin of the Trunk is sometimes visibly porous. But no where more, than in the better sort of walking Canes; where the Pores are so big, as to be visible even to the naked Eye: like to those, which are observable in several parts of the Ball of the Hand,* 1.3 and up∣on the ends of the Fingers and Toes.

6. §. THE Main Body of the Barque consisteth likewise of two Parts, sc. Parenchyma, and Vessels. The Parenchyma is made up of an innumerable company of small Bladders cluster'd together. Differing in nothing from those aforesaid in the Skin;* 1.4 saving, that they are much larger; and generally rounder.

7. §. This Parenchyma of the Barque is the same, as to its Sub∣stance, both in the Root and Trunk. Yet as to the Texture of its Parts, in the one, and in the other, there is This observable difference, viz. That in the Barque of the Root, cut transversly, the said Parenchyma (as hath been shew'd) is usually, more or less, disposed into Diametral Rays;* 1.5 running through the Barque, after the same manner, as do the the Hour-Lines through the Margin of the Dial-plate of a Clock or Watch: as in Marsh-Mallow, Lovage, Melilot, and others. Whereas here in the Barque of the Trunk, the said Parenchyma is rarely thus disposed into Dimetral Rays:* 1.6 Nor when it is, are those Rays continued to the Circumference of the Barque; as in the Barque of the Root they frequently are. So in Rhus or Sumach, although part of the Paren∣chyma be dispos'd into Diametral Rays:* 1.7 yet are those Rays extended not half way through the Barque. So also in Fig-tree, Worm-wood, Thistle, and others. What is further observable in the Texture of the Parenchyma, I shall shew in the description of the Pith.

8. §. THE Vessels of the Barque, are, as I shall also shew, diver∣sifyed many ways. But there are some Things, wherein, in all Sorts of Plants, they agree. First, in standing, most numerously, in or near, the inner Margin of the Barque. Secondly, in being always, and only Sap-Vessels. I have viewed so many, that at least, I can securely affirm thus much, That if there be any Heteroclital Plants, wherein they are found otherwise, there is not One, in Five Hundred. Thirdly, in be∣ing always Conjugated or Braced together in the form of Net-work. Al∣though the Number and Distances of the Braces, are very different: as I have already shewed in the Anatomy of Roots.* 1.8

9. §. THE Properties, whereby the said Vessels of the Barque are specificated and distinguished one from another, both in the same Plant, and in the several Species of Plants, are very many. Which Properties, are not Accidental, but such as shew the Constant and Universal Design of Nature. All which shall be demonstrated by the Description of several Quarters of the Slices, of so many Kinds of

Branches, cut Transversly: and by the several Figures which represent them.

10. §. FIRST then,* 1.9 for the Eleven first Quarters, the Vessels of the Barque are only of Two Kinds. And these, in the first Eight, seem to be Roriferous (described also in the Anatomy of Roots)a 1.10 and those which are common to most, if not to all Plants, sc. the Lymphae∣ducts. Yet in all the Eight, they are, in respect both of their Propor∣tion, and Position, very different. So in Hazel and Ash they are but few. In Holly and Barberry more. In Apple, Pear, Plum, Elm, still more numerous. And of those three Fruits, in an Apple, or Plum, more than in a Pear.

11. §. Again, as their Proportion, so likewise their Position is di∣vers. For in Holly, the Lymphaeducts or inner Vessels next to the Wood, stand in Rays.* 1.11 Yet so numerous and close together, as to make one Entire Ring. In Hazel, they stand more in Oblong Parcels. In Bar∣berry, they stand likewise in Parcels, but they are so many Half-Ovals, The utmost Vessels or Roriferous of all Three, make a Ring.

12. §. Again, in Apple, Pear, and Plum, the Lymphaeducts are Ra∣diated.* 1.12 The Roriferous are neither Radiated, nor make an entire Ring; but stand in Peripherial Parcels. Much after the same manner, they also stand in Elm.* 1.13 In Ash, the Vessels make Two Rings; but neither of them Radiated: the inmost Ring or Lymphaeducts, consisting of Ar∣ched Parcels, and the utmost or Roriferous Vessels, of Round ones. And whereas in all the foregoing, the Lymphaeducts are still contiguous to the Wood; and the Roriferous more or less, distant from the Skin: here, on the contrary, the former are distant from the Wood, and the latter contiguous to the Skin.

13. §. And that these Vessels in each Barque of the said Eight Bran∣ches, are of Two distinct Kinds, seems evident, as from some other reasons, so from hence; In that their Positions are altogether Heterogeneous: Yet in both Constant, Regular and Uniform. I say, there seems to be no Reason, why the self same Kind or Species of Vessels, should have a different, yea a contrary Position in one and the same Plant; and that Contrariety, not Accidental, but Regular and Constant.

14. §. FOR the Three next Quarters sc. the Ninth,* 1.14 Tenth and Eleventh, the Vessels of the Barque are also different in Number, Position, Size and Kind. In Pine, which is the Eleventh, they are fewer. In Walnut the Ninth, more. In Fig, the Tenth, most numerous.

15. §. So for their Position. In Pine, the inmost make a Radiated Ring. The utmost stand stragling up and down, without any certain order. In Wallnut the inmost make also a Radiated Ring; The ut∣most make a Double Ring; not Radiated, but of Round Parcels. In Fig, the inmost make also a Radiated Ring. But the utmost make a Double and sometimes Treble Ring, not of Radiated, nor Round, but Arched Parcels.

16. §. Thirdly, they are also different in Kind. Those, I think, of the two former, Wallnut and Fig, are thus different: those certain∣ly, of the Fig, are so; being Lymphaeducts and Lacteals. The Lymphae∣ducts make the inmost Radiated Ring. The outmost which make the other Rings in Arched Parcels, are the Lactifers.

17. §. That they are distinct Kinds of Vessels, is evident for two Reasons. First, from their Position in the Barque; which is altoge∣ther

different, as hath been said. Secondly, from the most apparent Diversity of the Liquors or Saps, which they contain, and which, upon cutting the Branch transversly, do distinctly Bleed from them. Which is one way, whereby we do distinguish the Vessels of Animals themselves. As in the Liver, it were hard to say, which is a Blood-Vessel, and which is a Bile-Vessel, where they are very small, if it were not for the Con∣tents of them both.

18. §. Those in the Barque of Pine, are likewise of Two Kinds. The inmost are Lymphaeducts, as in the two former. The utmost are not Milk-Vessels, but Gum-Vessels, or Resiniferous; which stand strag∣ling, and singly, about the midle of the Barque. Out of these Vessels all the clear Turpentine, that drops from the Tree, doth issue.

19. §. Few, but very great. So that besides the difference of their Number and Position, and of the Liquors which they contain, and Bleed; there is yet a Fourth, and that is, their Size. Most of these Turpen∣tine Vessels, being of so wide a bore, as to be apparent to the naked Eye: and, through a good Glass, above ⅓^d of an Inch in Diametre. Whereas that of the Lymphaeducts, can hardly be discovered by the best Microscope.

20. §. The same Turpentine Vessels of Pine, are likewise remarka∣bly bigger, not only than the Lymphaeducts, but many times, than the Milk-Vessels themselves: as those of the Fig, which, in comparison, are exceeding small; every Arch, not being a single Vessel, but a Parcel or Cluster of Vessels; Whereas one single Gum-Vessel in Pine, is sometimes as big as two whole Arched Clusters, that is, as some Scores of the Milk Vessels in a Fig-tree. And the said Gum-Vessels of Pine, being compared with the Lymphaeducts of the same Tree, one Gum-Vessel, by a mode∣rate estimate, may be reckoned three or four hundred times wider than a Lymphaeduct. The like prodigious difference may be observed in the Size of the several Kinds of Vessels of many other Plants.

21. §. THE Three next Quarters of Branches, are of Oak, Com∣mon Sumach, and Common Wormwood. In the Barque-Vessels whereof, there is observable some farther Variety. For in all or in most of the above named, there are only Two Kinds of Vessels in the Barque. But in Each of these, there are, at least, Three Kinds.

22. §. And first, in that of Oak there are Lymphaeducts, Rorife∣rous, and a Sort of Resiniferous. The inmost or Lymphaeducts, make a Radiated Ring,* 1.15 contiguous to the Wood. The utmost or the Rorife∣rous make also a Ring, but not Radiated. Those which are a sort of Rosin-Vessels, stand in Round Parcels; the greater Parcels betwixt the Two Rings of Roriferous and Lymphaeducts; and the lesser, betwixt the Roriferous and the Skin.

23. §. That these last are different Vessels from both the other, seems evident, from the difference of their Position, as aforesaid. And that they are a sort of Resiniferous, is argued from hence; In that, not only Galls are very full of Rosin, but that the Barque of Oak it self is also somewhat Resinous. For the conveyance of whose Resinous parts, it is most unlikely that any other Vessels should subserve, but a peculiar Kind; which may therefore be properly called Resiniferous.

24. §. The next is a Branch of Common Sumach.* 1.16 In the Barque whereof, there are likewise Three Kinds of Vessels. First of all, there is a thick Radiated Ring of Lymphaeducts; standing on the inner Mar∣gin

of the Barque, contiguous with the Wood. These Vessels exhibit their Lympha very apparently. A second kind of Vessels, sc. Roriferous, are situate towards the outer Margin of the Barque, and are composed into distinct Arched Parcels, all standing in a Ring.

25. §. Betwixt these Two Kinds stand the Milk-Vessels. Every single Milk-Vessel being empaled or hemmed in with an Arch of Rorife∣rous. The Milk-Vessels are extraordinary large, almost as the Gum-Vessels of Pine; so as distinctly to be observed without a Microscope; after they are evacuated of their Milk; and without difficulty will admit a Virginal Wyer; being two or three hundred times as big as a Lymphaeduct. Besides these Three sorts of Vessels, there is also a Ring, adjacent to the Skin; which seems to be another sort of Roriferous.

26. §. The Last,* 1.17 is a Branch of Common Wormwood. In the Barque whereof, there are likewise Three Kinds of Vessels. First of all, there is a thin Radiated Ring of Lymphaeducts, contiguous with the Wood or on the inner Margin of the Barque. Yet the Ring is not en∣tire, but made up of several Parcels; which are intercepted by as ma∣ny Parenchymous inserted into the Pith.

27. §. A Second Sort of Vessels, which seem to be Roriferous, are situate about the middle of the Barque: and are composed into Arched Parcels, which likewise stand all even in a Ring.

28. §. Beyond these Arches, and towards the outer Margin of the Barque, stand a Third Sort of Vessels. Different from the Milk-Ves∣sels in Sumach, both as to their Situation, Size and Content. For in Sumach, the Milk-Vessels stand within the Arched Lymphaeducts: whereas these in Wormwood, stand without them. Likewise, being the Vessels of an Herb, they are far less; sc. about the compass or width of a small Wheat-Straw. Their Content, is not a Milk, but a liquid, most Oleous and viscid Gum. Or which, for its pleasant Flavour may be called an Aromatick Balsom. For it perfectly giveth whatever is in the Smell and Taste of Wormwood: being the Essence of the whole Plant, which nature treasureth up in these Vessels. So that they are, in all respects, analogous to the Turpentine Vessels in Pine. There are divers other Herbs and Trees, which in the like Vessels, contain a Turpentine, or ra∣ther Aromatical Balsom; as Angelica, Helenium and others; the Vessels being so very large, that they may be easily traced with a knife, in cut∣ting by the length of a Branch or Saltk.

29. §. Whether in some Plants, there are not more Sorts of Ves∣sels, in the Barque, than have been now mentioned, I cannot say: Though we have not much reason to doubt of it. Because we see, there is so great variety in the Viscera of Animals. For what the Viscera are in Animals; the Vessels themselves are in Plants.

30. §. CONCERNING the Form and Texture of the Lymphaeducts, there are some things, which though they are best observed in the Wood, yet in regard I am now describing the said Vessels, I shall here therefore add. I have already said, and shewed, in the former Books, That the Lignous and Towy Parts of all Plants, are Tubulary. And that the Lympha is conveyed, by the length of a Plant, through an in∣numerable company of small Tubes or Pipes.

31. §. The Question may be yet further put: If the Towy Parts of the Barque are made of Tubes, What are these Tubes themselves made up of? I answer, That these Tubes or Lymphaeducts, are not only

themselves Organical; but their very Sides also, seem to be composed of other Parts, which are Organical, sc. of Lignous or Towy Fibres. Which Fibres,* 1.18 standing close or contiguous in a round Figure, they make one Tubulary Body, which I call the Lymphaeduct of a Plant. And it is probable, That these Fibres themselves, are also Tubulary. That is, that a Lymphaeduct, is a small Tube, made up or composed of other, yet much smaller Tubes, set round together in a Cylindrick Fi∣gure. As if we should imagine a company of Straws, which are so many small Pipes, to be joyned and set round together, so as to make another greater Pipe, answerable to a hollow Cane. The Cane, I say, is as the Lymphaeduct; and the Straws are as the Fibres whereof it is composed. By which also appears, the admirable smallness of these Fibres. For there are some Lymphaeducts, which may be reckoned fifty times smaller than a Horse-Hair. Allowing therefore but Twenty of the aforesaid Fibres to make a Thred so big as one Lymphaeduct; then one of the said Fibres, must be a Thousand times smaller than a Horse-Hair. That these Fibres, whereof the Lymphaeducts are made, are themselves made up of other Fibres, is not altogether improbable.

32. §. These Fibres, although parallel; yet are they not coalescent, but only contiguous; being contained together in a Tubulary Figure, by the We••tage of the Cortical Fibres, as in Chapter the Fourth will better be understood.

33. §. The first notice I took of the Composition and Texture of these Vessels, so far as the best Glasses yet known, will admit; was in a very white and clear piece of Ash-wood torn, with some care, by the length of the Tree, and objected to a proper Light. They seem also sometimes discernable in some other clear Woods, as in very white Fir, &c. And having formerly demonstrated, that the Lignous Part of a Plant, is annually made or augmented out of the inner part of the Barque, wherein the Lymphaeducts always stand: we may reasonably suppose the same Lymphaeducts to have the like Conformation in the Barque, as in the Wood.

34. §. And I am the rather induced to believe, that I am not mis∣taken in this Description, upon these two Considerations. First, that herein the Analogy betwixt the Vessels of an Animal and a Plant, is the more clear and proper. For as the Sanguineous Vessels in an Animal are composed of a number of Fibres, set round, in a Tubulary Figure, together: so are these Lymphaeducts of a Plant. Secondly, in that here∣in, there is a more genuine respondence betwixt these, and the other Vessels of a Plant it self; sc, the Aer-Vessels; which are made up of a certain number of Round Fibres, standing collaterally, or side to side as I have already observed in the Anatomy of Roots. So that it is the less strange, that the Lymphaeducts should be made up of Fibres, since the Aer-Vessels are evidently so made. Only with this difference, that whereas in the Aer-Vessels, the Fibres are postured or continued Spi∣rally: here, in the Lymphaeducts, they stand and are continued only in straight Lines.

35. §. THE STRUCTURE of the Lactiferous and Gum-Vessels, which have a very ample Bore, is more apparent. And, by the best Glasses I have yet used,* 1.19 they seem to be made, chiefly, by the Constipation of the Bladders of the Barque. That is to say, That they are so many

Chanels, not made or bounded by any walls or sides proper to them∣selves, as a Quil thrust into a Cork, and as the Aer-Vessels are in the Wood: but only by the Bladders of the Parenchyma; which are so postured and crouded up together, as to leave certain Cilyndrick Spa∣ces, which are continued by the length of the Barque.

36. §. One difference betwixt the Vessels or Chanels now describ'd, and the Tubulary Hollows and other Apertures in the Pith, is this; That these never exist originally with the Pith; but are so many Rup∣tures supervening to it in its Growth. Caused, partly, by the Stretch or Tenter it suffers from the Dilatation of the Wood:a 1.20 and partly, the drying, and so the Shrinking up of its Bladders, and of the Fibres whereof they are composed. Whereas the said Vessels in the Barque, are many of them originally formed therewith. And those which are post-nate, not made by any Rupture, but only such a Disposition of the Parenchymous Fibres, and Constipation of the Bladders, as is there∣unto convenient.

37. §. In paring the Barque of a Branch of Pine, Sumach, &c. they appear, neither parallel, nor any where Inosculated: but run, with some little obliquities, distinct one from another, through the length of the Branch: and so, we may believe, through the length of the Tree.

Notes

• * 1.1

  Tab. 20.
• a 1.2

  B. 2. P. 1. c. 3. §. 22.
• * 1.3

  Tab. 20.
• * 1.4

  Tab. 22. & Sequent.
• * 1.5

  Tab. 7, 8, 9.
• * 1.6

  Tab. 22. & Seq.
• * 1.7

  Tab. 31, 34, &c.
• * 1.8

  Chap. 3. Tab. 6.
• * 1.9

  Tab. 22. & Seq.
• a 1.10

  P. 1. c. 3. §. 22.
• * 1.11

  Tab. 22, 23, 24.
• * 1.12

  Tab. 25, to 28.
• * 1.13

  Tab. 29.
• * 1.14

  Tab. 30, 31, 32.
• * 1.15

  Tab. 33.
• * 1.16

  Tab. 34.
• * 1.17

  Tab. 3••.
• * 1.18

  Tab. 40.
• * 1.19

  Tab. 20.
• a 1.20

  B. 1. c. 3. §. 22, & 23.