XIV INTRODUCTION. 



64. The Corolla is usually of a thinner texture than the calyx, and variously 

 colored. Its leaves (Petals), when of the same nuinher as the sepals, alwavs 

 alternate with them. They are also often united by their contiguous margins, to 

 form a monopetalous corolla. 



65. When the calyx and corolla arc so nearly alike as not to be readily dis- 

 tinguished, they are collectively termed the Perianth. 



66. A Hower is complete when all its parts are present ; incomplete, when the 

 floral envelopes, or a part of them, are wanting ; perfect, when the stamens and 

 pistils are home in the same flower ; imperfect, or diclinous, when they are home 

 in Beparatc dowers; reyular, when the sepals or petals are of uniform shape and 

 size; and irregular, when they are unlike in shape or size. 



67. Imperfect flowers are further distinguished into monoecious, when those fur- 

 nished with stamens (siaminate or sterile flowers) and those furnished with pistils 

 (pistillate or fertile flowers) are borne on the same plant; diacious, when they are 

 borne on separate plants ; and polygamous, when both perfect and imperfect flow- 

 ers are borne on the same or different individuals. 



68. The manner in which the parts of the floral envelopes are arranged with 

 respect to each other in the bud is termed their ^Estivation. They are valvate, 

 when their contiguous margins meet, without overlapping ; induplicate, when 

 these project inwardly; reduplicate, when they project outwardly; imbricated, 

 when the margins of one overlap the adjacent- margins of the two next within ; 

 convolute, or twisted, when one edge of each piece covers the margin of the one 

 next before it, and the other edge is covered by the margin of the one next after 

 it ; and plaited, when the parts arc folded lengthwise. 



7. The Stamens. 



69. A Stamen consists of a sac, called the Anther, and, usually, a stalk, called 

 the Filament, by which it is supported. 



70. They are hyporji/nous, when they are inserted on the receptacle ; perigyncw, 

 when on the calyx; epigynous, when on the ovary ; ipipeta/ous, when on the co 

 rolla; and gynandrous, when they are united with the style. They are, also, 

 often combined with each other, either into ono set (monade/phous), or into two, 

 three, or more sets (diadelphous, triadelphous, &c.). 



71. The Anther is composed, commonly, of two united cells, which open in 

 various wars, and discharge a yellow, fertilizing powder, called the /'"Urn. The 

 part which connects the cells is the Connective. 



72. It is erect, or innate, when fixed by its base to tin' apex of the filament ; 

 a, finite, when fixed to the filament by its whole length; versatile, "hen fixed bj 

 the middle to the apex of the filaments on which it turns as on a pivot; introrse, 



when it faces inwardly toward the pistils; and extwrse, when it faces outwardly 



toward the petals. Occasionally, they are united into :i tube (syngenesious). 



73. Between the Btamens and the pistils i- often a fleshy expansion, called the 

 Disk. 



8. The PlHtlla. 



74. The Pistilfl OCCnpy the centre of the tlower. They arc inserted, singly ei- 

 in u whorl, on the receptacle ; or, when this is elongated or enlarged, they COVei 



its surface. 



