xiv INTRODUCTION. 



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

 colortd. Its leaves (I'dals), when of the same number as the sepals, always 

 iilteniatc with them. They aii; also often united liy their eontiguous margins, to 

 form a tnonopetaluus corolla. 



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

 tinguished, they are colleetively termed the Ptrlnnth. 



G6. A tiower is com/ilcte when all its parts are present ; iucom/ihlc, when the 

 Horal enveloi)es, or a part of them, are wanting ; perfect, when the suimens and 

 pistils are borne in the same flower ; impcrftct, or diclinous, when they arc borno 

 in separate flowers ; reyular, when the sej)als or petals are of uiiifmin shape and 

 size ; and iirer/ular, when they arc unlike in shape or size. 



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

 nished with stamens (staminate or sterile Jloivers) and those furnished with |)istils 

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

 borne on separate plants ; and pohjfjmhous, when both j)erfect and imjierfcct flow- 

 ers are borne on the same oriliflerent 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 ; indiiplicate, 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 are 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 hi/pogj/nous, when they are inserted on the receptacle ; perigynous, 

 when on the calyx ; epigynoiis, when on the ovary ; epipetalous, when on the co- 

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

 often combined with each other, either into one set (monadelphous) , or into two, 

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



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

 various ways, and discharge a yellow, fertilizing powder, called the Pollen. The 

 part which connects the cells is the Connective. 



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

 adnate, when fixed to the filament by its whole length ; versatile, when fixed by 

 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 extrorse, when it faces outwardly 

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



7.3. Between the stamens and the pistils is often a fleshy expansion, called the 



Disk. 



8. Tlie Pistils. 



74. The Pistils occupy the centre of the flower. They are inserted, singly or 



in a whorl, on the receptacle ; or, when this is elongated or enlarged, they cover 



its surface. 



