Book I. 



INTERNAL STRUCTURE OF PLANTS. 



21;^ 



so that, in tlie revolution of ages, even the surface of tlie barren rock is covered with a soil 

 capable of supporting the loftiest trees. 



1335. The 'Fungiform a tribe of plants whose herbage is a frond of a fleshy or pulpy texture, quick in its 

 growth and fugacious in its duration, and 

 bearing seeds or gems in an appropriate 

 and exposed membrane, or containing them 

 interspersed throughout its mass. This 

 assemblage of plants may be regarded 

 as the lowest in the vegetable scale, ex- 

 hibiting a considerable resemblajice to 

 the tribe of zoophites, and thus forming 

 the connecting link between the vegetable 

 and animal kingdoms. The habitations 

 they affect are very various, many of them 

 vegetating on the surface of the earth 

 {fig. 181. a), and some of them even buried 

 under it ; others on stumps and trunks of 

 rotttn trees (6) ; others on decayed fruit ; 

 others on damp and wet walls ; and others 

 on animal ordure. 



1336. UsesoftheVungL The pow- 

 der of the lycoperdons is said to be 

 an excellent styptic ; and is remarkable also for its property of strongly repelling moisture. 

 If a basin be filled with water, and a little of the powder strewed upon the surface so as to 

 cover it only, the hand may be plunged into it and thrust down to the bottom without 

 being wetted with a single drop of water. Several of the boleti, when dried, afford 

 a very useful tinder ; and several of the agarics and tubers are used as articles of food, 

 or as ingredients in the preparation of seasoning. The truffle is much esteemed for the 

 rich and delicate flavour which it imparts to soups and sauces ; and the mushroom and 

 morel for their esculent property, and their utility in the preparation of catsup. 



Sect. III. Of the Internal Structure of Plants. 



1337. The organs of plants discoverable by external examinatioji are themselves reducible 

 into component organs, which are again resolvable into constituent and primary organs. 

 These are called the decomposite, the composite, and the elementary. 



SuBSECT. 1. Decomposite Organs. 



1338. The decomposite organs are distinguishable on external examination, and con- 

 stitute the vegetable individual ; to the dissection of which we will now proceed, in 

 the order of the seed, pericarp, flower, leaf, gem, and caudex, with their decomposite 

 appendages. 



1339. The seed. The mass of the seed consists of two principal parts, distinguishable without much diffi- 

 culty ; namely, the mteguments and nucleus, or embryo and its envelopes. 



1340. The integuments proper to the seed are two in number, an exterior integument and an interior 

 integument. 



1341. T/<(? exterior integument, or testa, is the original cuticle of the nucleus, not detachable in the early 

 stages of its growth, but detachable at the period of the maturity of the fruit, when it is generally of a 

 membranaceous or leathery texture ; though sometimes soft and fleshy, and sometimes crustaceous and 

 bony. It may be very easily distinguished in the transverse or longitudinal section of the garden bean or 

 any other large seed. 



1342. The interior integument, or membrana, lines the exterior integument, or testa, and immediately 

 envelopes the nucleus. Like the testa, to which indeed it adheres, it may be easily distinguished in the 

 garden \ni3iX {fig. 182.), or in a ripe walnut ; in which latter it is a fine transparent and netUke membrane. 



1343. The mccleus is that part of the seed which is 

 contained within the proper integuments, consisting 

 of the albumen with the vitellus, when present, and 

 embryo. 



1344. The albumen is an organ resembling in its 

 consistence the white of an egg, and forming, in most 

 cases, the exterior portion of the nucleus, but always 

 separable from the interior or remaining portion. 



1345. The vitellus is an organ of a fleshy but firm 

 contexture, situated, when present, between the al- 

 bumen and embryo; to the former of which it is 

 attached only by adhesion, but to the latter by incor- 

 poration of substance, so as to be inseparable from it, 

 except by force. ^^ 



1346. The embryo, which is the last an^Btot essen- 

 tial part of the seed, and the final object ql^e fructi- 

 fication, as being the germ of the future plant, is a small and often very minute organ, enclosed within the 

 albumen and occupying the centre of the seed. 



13A1. The cotyledon, or seed-lobe {b), is that portion of the embryo that encloses and protects the plant- 

 let, and springs up during the process of germination into what is usually denominated the seminal leaf, 

 if the lobe is solitary; or seminal leaves, if there are more lobes than one. In the former case the seed 

 is said to be monocotyledonous ; in the latter case, it is said to be dicotyledonous. Dicotyledonous 

 seeds, which constitute by far the majority, are well exemplified in the garden bean. As there are 

 some seeds whose cotyledon consists of one lobe only, falling short of the general number, so there are 

 also a few whose cotyledon is divisible into several lobes, exceeding the general number. These have been 

 denominated polycotyledonous seeds, and are exemplified in the case of Lepidium sativum or common 

 ^rden cres.s, in which the lobes are six in number ; as in that also of the different species of the genus 

 Plnus, in which they vary from three to twelve. 



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