08 



HISTORY OF THE VEGETABLE KINGDOM. 



is also a circumstance of material importance to 

 the botanist. In the tulip, and in the generality 

 of plants, they are nearly of the same length in 

 the same flower ; but there are some in which 

 their lengtlis are unequal. This is the case in 

 the genus mentha, (as peppermint) in which, 

 ut of four stamens, two are always shorter than 

 the others. The same is the case in the classes 

 didynamia and tetradynamia ; in the latter, of 

 six stamens two are always shorter, forming a 

 remarkable character of the crucifoi-nr plant. If 

 compared in their proportions with the other 

 parts of the flower, the stamens are sometimes 

 found to equal the calyx or corolla in their 

 length, as in the genus polygomtm ; sometimes 

 they are found to overtop it, and in other cases 

 to fall short of it. In many flowers certain of 

 the stamens are always abortive, as in Virginian 

 spider-wort, sage, rosemary &c. The stamens, 

 though vei-y different in their shape and struc- 

 ture from the petals, exhibit, however, strong 

 indications of being nearly allied to them, and 

 seem in some cases, as in the flower of nymphea 

 alba, or water lily, to run mutually into each 

 other, the inner petals being paitly stamen, or 

 the outer stamens being partly petals. But in 

 many flowers, particularly the polypetalous, 

 the stamens are entirely convertible into distinct 

 petals, and are often so converted either in part 

 or in whole. In the foimer case the flower is 

 said to be double, in the latter case it is said to 

 be full. But this singular conversion of stamens 

 into petals, is regarded by the botanist as alto- 

 gether an aberration from the laws of vegetable 

 economy, and is found to occur but seldom ex- 

 cept in consequence of culture. The anemone, 

 ranunculus, and rose, when cultivated in our 

 gardens, afford examples of the flowers of this 

 description. They are more showy indeed, and 

 more generally admired than the flower in its 

 natural state, and are consequently the object of 

 the peculiar care of the florist ; but they are 

 regarded by the botanist as being only vegetable 

 monsters. 



The filament, d, is the elongated, slender, and 

 threadlike stalk which supports the anther. It 

 is not an essential part of the stamen, being in 

 many cases absent. According to its various forms, 

 it is distinguished into flattened, wedge-shaped, 

 awl-shaped, capillary. The anther is generally 

 attached to the tip of the filament ; but some- 

 times the latter is prolonged above the insertion 

 of the anther. The stamens are in general free 

 and unconnected with each other; but in certain 

 cases they are more or less united by means of 

 the filaments. 



When the filaments are all connected together, 

 either by the sides or at the base, they are said 

 to be monadelphoiis, as in the mallow, fig. a. 

 When the filaments are united into two distinct 

 ijortions, they are said to be diadilplioios, as in 



the common pea and fumitory, as fig. b. 'Wlien 



41. 



united into three or more bundles, they are 

 temied polydelphous. 



The colour of the filament is generally white, 

 as in the convolvulus ; but in the peach it is 

 spotted, and in the medlar tree red. In some 

 stamens the filaments are elastic, unbend- 

 ing themselves with considerable force as the 

 corolla expands, as in the genus Urtica; and 

 in some they are susceptible to the action of 

 external stimuli, as in those of the barberry, 

 which, if touched with the point of a needle 

 or other fine instrument on the inner side, and 

 near the base, wiU spring forwai-d immediately 

 with a sudden jerk to the centre of the flower. 

 The anther, e, is the essential part of the 

 stamen, and contains the pollen or fecundating 

 powder. It is generally formed of two mem- 

 branous bags attached to each other by their 

 sides, joining or united by an interposed body. 

 Each of these bags or cells is divided internally 

 into two parts by a partition, which cells open 

 at the period of fecundation to allow the pollen 

 to escape. 



Sometimes the anther consists of only one 

 cell, as in the hazel, mallow, and pine ; more 

 rarely there are four cells, as in butomus mnbel- 

 latus. Each of the cells have on one side a lon- 

 45 gitudinal groove, where the opening 



, takes place. Sometimes the pollen 

 escapes by pores or slits in the 

 summit of the anther, as in the 

 heaths, the potatoe, &c. ; in other 

 cases their pores are furnished with 

 immovable valves, as in the bar- 

 berry, laurel, and cpimedmm al- 

 pimim. In fig. 45, a a, are the 

 pores in the anther ; b b, the mov- 

 able and elastic valves. 

 The anther is attached to the fila- 

 ment in various ways, as by its base, 

 middle, or summit. The anthers 

 sometimes are imited together so as 

 to foi-m a continuous tube. This is 

 the case in the family of the syngen- 

 esia, as the daisy, marygold, thistle, 

 &c. 



The Pollen, or the substance contained in the 

 cells of the anther, and which is subservient to 

 fecundation, generally presents the appearance 

 of a powder, composed of extremely minute 



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