1508. Taken in a strict sense all the diversity of vegetable structure of vegetables has reference first of all to the difference in the tissues; these being either unseparated, or separated, into special systems and members. At first the tissues lie confusedly, or without order, amongst themselves. They then _separate_ in a concentric and tubular form into systems, that are encased _within_ each other, like the bark, liber, and wood, which form the _shaft_. Furthermore they separate into members, and appear one _above_ the other, as root, stalk, and foliage, which collectively may be called the _stem_; these are repeated as seed, pistil, and corolla, which together are called _flower_, and combined, _fruit_, namely, nut, plum, berry and apple. I designate by the term _stock_ or trunk all the parts as far as the blossom; and this together with the fruit I name thyrsus. The vegetable stock, whose tissues have not yet separated into members, I style, from want of a better word, _thallus_. As we divide political kingdoms into _provinces_ and _circles_, so also may these titles be suitably applied here. It is evident, that the plants which simply consist of tissues and have as yet no sheaths and members, are the _Acotyledones_; those, however, provided with sheaths, but devoid of true roots, stalk, and foliage, _Monocotyledones_; those with true foliage or reticular-veined leaves are, on the contrary, _Dicotyledones_. The natural system of vegetables stands accordingly in the following manner. A.--STOCK-PLANTS. Province I. HISTOPHYTA, OR TISSUE-PLANTS--Acotyledones. Class 1. Cell-plants. 2. Duct- 3. Trachea- II. THECOPHYTA, OR SHEATH-PLANTS--Monocotyledones. 4. Bark-plants. 5. Liber- 6. Wood- III. ARTHROPHYTA, OR MEMBER-PLANTS--Dicotyledones. Circle 1. _Axis-plants_--Tubulifloræ. 7. Root-plants. 8. Stalk- 9. Leaf- B.--BLOSSOM-PLANTS. Circle 2. _Flower-plants_--Thalamopetalæ. 10. Seed-plants. 11. Ovarium- 12. Corolla- Circle 3. _Fruit-plants_--Calycopetalæ. 13. Nut-plants. 14. Plum- 15. Berry- 16. Apple- 1509. A slight glance at the above table shows us the procedure of Nature. The higher she ascends, the more and more she separates, and thereby increases, the organs. There may therefore be plants which have only a single organ or tissue, as well as others, which possess all.