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. III. Of the several COVERS of Seeds, and of the VI∣TELLUM.

THE next step of Natures Managery, relates chiefly to the Growth of the Seed when it is sow'n. For which purpose, the outer Covers are somewhere furnished with Apertures sufficient for the recep∣tion of Alimental Moyster from the Ground; and Divisions, for the shooting forth of the young Root into it. As in the Seed of a Gourd, at the Bottom; in a Bean, on the Side; and in a Ches∣nut, at the Top: in which places the Radicle or young Root always lies and puts forth, in the said several Seeds. And the Seed of Palma Christi; which falls to the Ground not only in the usual Covers, but also in the Seed-Case, for the more plentiful admission of Aliment, hath a double Aperture. Not much unlike to this, is that found sometimes

in larger parcels of Euphorbium; for which Cause, I suspect it to be the Gumm of a Plant of the Tithymal kind.

2. §. If the Cover of the Seed be stony and very hard, it is also distinguished into several Pieces; whereby they easily cleave asunder without much resistance to the eruption of the Root. So the Shell of a Hazel-nut easily cleavs on the edg; and the cleft begins best at the poynt, where the Root stands and shoots forth. The Shell of some Walnuts cleavs into three Parts; and the Stone of the Bellerick Myro∣balan into five: that so, being very thick and hard, if one piece should not yield, another may not fail to do it. And the Covers or Husks of some sorts of Grain, as of Millet, are only folded or laped one over another, the better to give way to their tender Sprouts.

3. §. Besides the Kernels of Plums and some other Fruits, there are very many Seeds, even of the smaller sort, which have also stony Covers; as of Carthamum, Myagrum monospermon, Beet, Borage, Lithosperme, Amaranthus, Violet, &c. Sometimes, for the reception of the harsher and less matured Principles from the Seed, in its Generation, as in Borage. Commonly, to keep it warmer before and after its sow'n. For which purpose, the outer Covers of some Seeds, are as it were Lined with Fur: in that of Great Maple, Short; of Gossipium, Long. And if the Seed requires a longer stay under ground, the hardness of the Cover serves to stint the Aliment; lest too much, should either rot it, or cause it to germinate, before its proper season, or full time for a more Masculine Growth.

4. §. On the contrary, many Seeds, as those of Clary, Garden•• Cress, and others of that Tribe, have their upper Covers faced with a Mucilage: which being easily receptive of any Moysture in the Ground, gradually swells, till it lies like a Gelly round about the Seed. Ei∣ther for a more plentiful supply of Aliment; or at least, to soften the Covers, the better to accelerate the Growth of the Seed.

5. §. The process of Nature in the several steps of the Vegetation of the Seed, hath formerly been explained.a

6. §. THE COVERS of all, or at least the far greater num∣ber of Seeds, are Three; some way or other derived from the Pith: as shall hereafter be seen. And sometimes, Four: even those of ston'd Fruits, have Three, besides the Stone. In that of Gossipium, there are Two Coats under that lined with the Cotton. The Seeds of Cucumer, Goats-beard, Broom, Scabious, Lettice, &c. although so small, have plainly Three Coats. But in some of these, and many more, there are only Two distinctly visible, except in the State of Generation.

7. §. In the Upper Coat, the Seed-Vessels are disseminated. The Second, is first a meer Pulp; but afterwards shrinks up and sticks close to the upper. The Third or Inmost is more dense; and if it be thin, for the most part, transparent; whereby the Seed seems sometimes to be naked while it lies therein; as in Almonds, Cucumers, and the like. For this sticks not to the midle Coat, as that doth to the outer; but commonly, remains entire, after those are stripp'd off, being as it were, the Smock of the Seed.

8. §. In Melissa and some other small Seeds, it comes finely off up∣on soaking in warm Water or on the Tongue. In Fenugreek, 'tis soft, and of an Amber-Colour; and being moystened, looks almost like fine Glew. But commonly, tis a prety tough Membrane, and often with

some thickness, as in Plums, Borage, Scabious. Yet always extream thin at the Tip of the Radicle; the more easily to break and yield to it, as the Secundine to the Foetus, when it first shoots into the Ground. And sometimes, as in the Seeds of an Orange, it hath at one end, the resemblance of a Placenta. But of this, and the two upper Coats, I shall give a further Description in the last Chapter.

9. §. AS ALL Seeds are ex Ovo; so there are many with thin Covers, as of Orach, Spinage, Beet, and the rest of that Tribe, &c. which besides the Albumen or clear Liquor out of which they are bred; have also, a Vitellum, or a Body thereunto Analogus: being neither part of the Seed, nor part of the Covers, but distinct from them both. With respect to the Bulk of the Seed, very large, as white as Starch, and pret∣ty friable, like good Rice or Barley: of a roundish Figure, and grooved on the Girth, so as to have a double Edge; Whereby the Seed, which is long and slender, lies round it, as a Sack of Corn upon a Pack-Saddle or a Rope upon a Pully-wheel. Upon my first notice hereof, it seemed to answer to a Placenta. But upon further consideration, the Analogy doth not hold betwixt them. For the Placenta lies without the Mem∣branes in which the Foetus is conteined: whereas this body lies within the Covers contiguous to the Seed, and so becomes its first and finest A∣liment, as the Yelk doth to the Chick. For which purpose, as in the Ge∣neration of the Seed, it is a pure Milky Chyle; So in its Vegetation, it is converted into the like again.

10. §. The same Body for Sustance, is observable in the Seeds of Rhapontick, Dock, Sorrel, and the rest of that kindred, with this dif∣ference; That whereas in Orach, &c. the Seed only lies upon it; here, the main Body or Lobes of the Seed are immersed therein, the Radicle standing naked or above it. So that the said Lobes, and therein the Seminal-Root are beded herein, as in a Tub of Meal or a little pot of pure refin'd Mould, necessary for the first Vegetation of the Radicle.

11. §. BY THESE midle Steps, Nature proceeds from the Thiner Covers of Seeds; or those, which after the Generation of the Seed is finished, shrink up; to the Bulky Kind, or those which keep their Bulk after they are dry. Wherein, not only the Lobes, as in Dock, but the whole Seed is immediately lodged. Different in Sub∣stance, Shape and Bulk; but always many times biger than the true Seed within it: for which it is commonly mistaken; but is no more the Seed, than is the Stone of a Plum, the Kernel.

12. §. In the Barbado Nut, 'tis White, Soft, Conick-oval, and ta∣king all its Dimentions, 8 or 10 times bigger than the Seed within it. In Ashen Keys, 'tis of a sad Colour, hard, yet somewhat Oyly, Oval and flat, and of the same Bigness as in the Barbado Nut, with respect to the Seed. In the Fruit commonly called Nux Vomica Officinarum, 'tis of the Colour and Hardness of a Cows-Horne; and makes almost the whole Body of the Fruit, being about 14 or 15 times the Bulk of the Seed. In Goosgrass or Cliver 'tis of the like Horny Substance, but shaped some∣what like a Bonet with the Rimm tuckt in. And so in a Coffee-Berry; but rowled or foulded up into a kind of Oval Figure, with a Notch or Ri∣ma through the Length, where the two Ends meet. With other diver∣sities which will best be understood, when I come presently to the De∣scription of the Seed herein contained.

13. §. With respect to the use of this Cover, it is observable, that where there is a Stone or Shell over it, as in the Barbado Nut, it is soft; but where there is none, as in Nux Vomica, Ash, &c. 'tis hard; and so it self instead of a Stone. As also, That it becomes hard, only by the proper Nature of its Parenchyma, and the exquisite smallness of the Bladders of which it consists. Whereas a Stone, is also hardened by the Less or Tartar of the Sap which sinks into it, and thereby petrifies it a as hath been said. So that whereas a Stone, as it lies in the Ground, only cleavs in certain Places, but continues hard: This Cover, like some Horns, upon the due accession of Moisture, doth gradually become soft. Whereby, as while it is hard, it performs the Office of a Stone, in guarding the Seed til the proper Season for its Growth: So after∣wards when it is soft, it answers, as in Orach or Dock,b to a Vi∣tellum, from whence the Seed receiveth its first and purest Aliment.

Notes

• Tab. 72.
• Tab. 72.
• Tab. 75.
• a

  B. 1. Ch. 1.
• Tab. 75.
• Tab. 76.
• Tab. 75.
• Tab. 75.
• Tab. 75.
• Tab. 76.
• Tab. 77.
• a

  P. 3. Ch. 3.
• b

  Ch. 3. §. 8, 9.