300 



PHY 



THE UNIVERSAL HERBAL; 



PHY 



it, how different soever may be the circumstances of its ger- 

 mination. The sketch of the shoot is narrowly circumscribed 

 by nature, and nothing is capable of producing an alteration 

 in its parts. The same form will be retained, and propa- 

 gated for ever. A seed has integuments, corcle, and coty^ 

 ledons. It is fastened by an umbilical cord; and as soon as 

 this separates, a cicatrice remains, called the Eye. In its 

 vicinity lies the corcle. In the hardest seeds this last spot is 

 the only one not covered by the internal hard membrane. 

 When the seed is placed in the ground, moisture soon per- 

 vades its substance through this aperture, assisted by the 

 warmth of the atmosphere. In the corcle and cotyledons, all 

 the described vessels are present. In the last, the adducent 

 and air vessels divide themselves into numerous bundles, 

 which frequently anastomose in the manner peculiar to the 

 plant. A cellular membrane covers on both sides those ves- 

 sels which spread on one plain surface, and contains the 

 reducent vessels. On both surfaces the lymphatics spread 

 out and surround the apertures of the cuticle. The per- 

 vading moisture is communicated to the vessels; the water 

 is decomposed by them, and hydrogen and oxygen trans- 

 pired. Carbonic acid gas, which seems to be shut up in 

 the neighbourhood of the umbilicus between the external 

 and internal membranes of the seed, is likewise partly set 

 free. The intercepted air which was received from ger- 

 minating seeds, contained, in 10 cubic inches, sometimes 

 2, sometimes 3, 5, even 8 cubic inches of carbonic acid 

 gas, and from 5 and 6 to 8 cubic inches of azote and 

 hydrogen gas mixed. This gas, when mixed with atmo- 

 spheric air, explodes at the approach of flame. The rest of 

 the undecomposed water, with the fixed part of carbon and 

 hydrogen, pervades the vessels more and more, reduces the 

 substance of the seed to a milk-white fluid, occasions a sti- 

 mulus, and by the irritability of the vessels, excites the 

 action of the vital power. The vessels, filled with their sap, 

 carry it to the corcle, which is elongated by it, and con- 

 verted into a plant. The corcle consists, we know, of the 

 rostel and the plumule. From the first arises the root; from 

 the last the trunk, or the part above ground. Cutting a 

 germinating plant in a perpendicular direction, so as to 

 divide it into equal parts, we observe in the middle of each 

 cotyledon a hollow channel, which is called the chyliferous 

 duct, which is continued as far as the beginning of the rostel, 

 proceeds between its pith and fleshy substance, and at last 

 incloses the pith. This duct serves to convey the nourishing 

 fluid, which the cotyledons contain, to the young plant. 

 Experience teaches us, that germinating plants, even though 

 they have some leaves already evolved, cannot part with 

 their cotyledons without endangering their lives; like a young- 

 animal, which cannot want the feeding breast of its mother. 

 It is a remarkable phenomenon in the germination of seeds, 

 that the radicle first elongates, and pushes into the earth, 

 where, as soon as it fixes itself, the plumule appears in its 

 peculiar shape. Even though the seed should be inverted 

 and put into the ground, so as to turn the rostel towards the 

 surface, yet it never will grow upwards. It grows long, but 

 soon turns the seed, and goes into the ground, so that it 

 recovers its proper position. This observation, which may 

 be made every day, especially in the Kidney Bean, in the 

 Common Bean, and other culinary seeds, has greatly attracted 

 the attention of botanists. It is to be observed, that seeds 

 are not all provided with the rostel, especially those of some 

 aquatic and parasitic plants, and perhaps all those which 

 Dr. Gsortner styles acatyledoncs. I was, as far as 1 know, 

 the first who discovered this by examining with great care 

 the Water-caltrops, (Trapa naians,) one of the most singular 



plants. The nuts, as they are called, of this plant, when 

 they lie in water, the natural habitation of the plant, shoot 

 forth a long .plumule, which in a perpendicular direction 

 rises towards the surface of the water, its sides pushing out, 

 at certain distances, capillary branched leaves. Some of 

 those leaves bend downwards, and take firm root at the 

 bottom. In this case then the plant becomes fixed in the 

 ground, not by a peculiar root, which, like the rostel, pre- 

 existed in the seed, but only through the leaves. It would 

 be as difficult as in the rostel, to state the reason why some 

 of the undermost leaves bend downwards, and by their capil- 

 lary extremities shoot forth roots. From this, however, we 

 are enabled to conclude, that some seeds may support the 

 want of the rostel ; but that a germinating seed can exist 

 without plumule and cotyledons, is a supposition altogether 

 inadmissible. Nobody as yet has attempted to deny the 

 existence of the plumule in any seed. Linneus, Gartner, 

 Jussieu, and many other botanists, denied that of the coty- 

 ledons, especially in the plants belonging to the class Cryp- 

 togamia. Jussieu alone adds to those plants which have no 

 cotyledon, (Gsertner's acotyledones,) such as want the rostel. 

 Nature has provided plants with their cotyledons, that these 

 might nourish the young plant in its tender infancy. Never 

 yet have I met with a single instance where this wise measure 

 of nature was omitted. I examined purposely all those 

 plants which were said to want cotyledons, and always found 

 them. That in some plants the existence of the cotyledons 

 was altogether denied, and others were said .to have one 

 only, others two, and several plants more than two, arose 

 partly from inaccurate observation, partly from mistaking a 

 part of the plumula for a cotyledon. Placenta, or cotyledon, 

 is the name of the whole substance of a seed, not including 

 the parts of the corcle. It rises in many plants with the 

 plumule above ground, and is converted into leaves; or, it 

 remains in the ground, and, as in the Gramina and Lilies, the 

 first leaf of the plumule only rises, and this is what some 

 thought to be a cotyledon. In Flax, and the species of Fir, 

 both cotyledons are converted into leaves, and the leaves of 

 the plumula are evolved immediately after them, and are of 

 the same magnitude and appearance. Hence it was, that 

 botanists supposed there were many cotyledons. The divi- 

 sion, therefore, of plants into acotyledones, monocotyledones, 

 dicotyledones, and polycotyledones, is erroneous. I am 

 acquainted only with three varieties, which are discovered 

 in the cotyledons of the germinating seed. The cotyledons 

 are either split into two parts, or they adhere so firmly to 

 one another, that they cannot be separated. In the first 

 case, they grow out of the earth till they become visible, and 

 assume the appearance of leaves: these are denominated by 

 botanists dicotyledones, and the same process takes place in 

 the most of plants. As a very common example, I may adduce 

 the Kidney Bean, Phaseolus vnlgaris. In the second case, 

 they remain in the ground, and only the plumule grows up, 

 as in the Vetch, Vicia sativa, in the Pea, Pisum sativum, in 

 all the Gramina, Lilies, &c. In the third case, the cotyledons, 

 or the two halves of the seed, are not divided, but pushed 

 upon the ground, and on their side the plumule is evolved, 

 as in Juncus, &c. &c. I have not been able to perceive any 

 more varieties, and every one may easily satisfy himself of the 

 truth of what I have mentioned. I have observed, according 

 to the changes in the cotyledons, five principal varieties, 

 which I call membraneous corclcs; filiform corcles ; split cor- 

 cles; earth corcles; and globular corcles; viz. Dcrmoblasta-, 

 I call such as have the cotyledon in form of a membrane, 

 which bursts in an irregular manner. This membrane is 

 found in the Fungi, where, in general, it disappears imme- 



