318 Rev lew of Gray^s Botany. 



Succeeding the preface, in which the plan of the work is 

 exhibited and many important items specified, is an introduc- 

 tion, consisting of brief outhnes of botany, which contain 

 very vahiable matter to the beginner, and explain, in a man- 

 ner easy to be understood, much that is curious in vegetable 

 physiology. Under the several sections, the following sub- 

 jects are treated :— " 1. Plants in general. 2. Organs of 

 Vegetation in general. 3. The Root. 4. The Stem : * its 

 external modifications; ** its internal structure. 5. The 

 leaves : * their nature and structure ; ** their conformation 

 and parts; *** their arrangement, duration, &c. ; **** stip- 

 ules. 6. The Organs of Reproduction. 7. The Infloresence. 

 8. The Flower : * its component parts, structure, &c. ; ** its 

 symmetry; *** internal structure of the pistil, &c. ; ***=* 

 ovules, fertilization. 9. The Fruit. 10. The Seed. 11. Cryp- 

 togamous, or flowerless plants. 12. Classification and No- 

 menclature. 



Under the section, treating of the ovules and fertilization, 

 we find the following facts of much interest to the practical 

 and experimental florist : — 



179. The ovules are fertilized through the agency of the pollen. The 

 pollen grains, that fall upon the stigma or some of them, soon emit, through 

 some part of their thickish outer coat, a delicate prolongation of the thin 

 and extensile inner coat, in the form of a slender tube, filled with the fluid, 

 which the grain contains, and with the minute molecular matter that floats in 

 it ; this tube penetrates the stigma, and imbeds itself deeply in the loose 

 tissue of the style. Shortly after, similar tubes or threads, generally sup- 

 posed to be prolongations of these, are found in the placenta, whence they 

 have been often traced into the orifice of the ovule, or into contact with the 

 projecting apex of the nucleus, in which the nascent embryo subsequently 

 appears, first as an apparently single cell or vesicle of cellular tissue, sus- 

 pended by a thread-like chain of smaller cells. This primary cell soon 

 gives rise to a mass of minute cells, which, as they increase and grow, are 

 at length fashioned into the ultimate and specific form of the embryo. — 

 (p. xxxi.) 



The arrangement of the species is after the natural method, 

 and no indication of the Linnsean or sexual system appears 

 in connection with them. This, we have heard suggested to 

 be a defect, especially in consideration of the beginner ; but 

 to obviate in some measure the objection which, at first sight, 



