THE FLORAL ENVELOPS, OR PERIANTH. 



488. PERIGYNIUM is the name given 

 to the urceolate perianth of Carex, in- 

 vesting the ovary but allowing the style 

 to issue at its summit. It is evidently 

 composed of two united sepals. 



489. GLUMES AND PALES represent 

 the floral envelops, or rather the invo- 

 lucre of the Grasses. Their alternating 

 arrangement clearly distinguishes them 

 from a perianth. They occur in pairs, 

 the smaller usually above. The glumes 

 envelop the spikclet, the pales the single 



334, Flower ofSclrpus lacnstris, mag- 



flower, and often within the pales are nified; consisting of six seta;, three sta- 



two or three scales representing the mens ' three ^ stils unite<1 ' except tbe 



stigmas. 335, Flower of Carex rivularis 



perianth, surrounding the stamens and s, with g, its giume,p, its bottle-shaped 

 ovary, all which are illustrated in the Pgynium, 2-toothed at top, enveiop- 



" ing the triple ovary ; stigmas, three. 



wheat. (195.) 



490. THE DURATION of the calyx and corolla varies widely, and is 

 marked by certain general terms. It is caducous when it falls off im- 

 mediately, as the calyx of poppy, corolla of grape ; deciduous when it 

 falls with the stamens, as in most plants ; and persistent if it remain 

 until the fruit ripens, as the calyx of apple. If it continue to grow 

 after flowering, it is accrescent, and if it wither without falling off it is 

 marcscent. 



CHAPTER XII. 



OF THE ESSENTIAL ORGAN'S. 

 THE STAMENS, OR ANDRCECIUM. 



491. POSITION. Within the safe inclosure of the floral envelops 

 stand the essential organs the stamens and pistils, clearly distinguish- 

 able from the perianth by their more slight and delicate forms, and 

 from each other by various marks. In the complete flower the andrce- 

 cium next succeeds the corolla in the order of position, being the third 

 set, counting from the calyx. 



492. A PERFECT STAMEN consists of two parts the filament, corre- 

 sponding with the petiole of the typical leaf, and the anther, answering 

 to the blade. Within the cells of the anther the pollen is produced, a 

 substance essential to the fertility of the flower. Hence the anther 

 alone is the essential part of the stamen. 



