xiv INTRODUCTION. 
64. The Corolla is usually of a thinner texture than the calyx, and variously 
colored. Its leaves (Petals), when of the same number as the sepals, always 
alternate with them. They are also often united by their contiguous margins, to 
form a monopetalous corolla. 
65. When the calyx and corolla are so nearly alike as not to be readily dis- 
tinguished, they are collectively termed the Perianth. 
66. A flower 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 borne in the same flower ; imperfect, or diclinous, when they are borne 
in separate flowers ; regular, 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 monacious, when those fur- 
nished with stamens (staminate or sterile lowers) and those furnished with pistils 
( pistillate or fertile flowers) are borne on the same plant; diecious, when they are 
borne on separate plants; and polygamous, when both perfect and imperfect flow- 
ers are borne on the same or different individuals. ee : 
68. The manner in which the parts of the floral envelopes are arranged with 
respect to each other in the bud is termed their ZEstivation. 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 are folded lengthwise. 
| eee es 7. The Stamens. 
69. A Stamen consists of a sac, called the Anther, and, usually, a stalk, called 
the Filament, by which itis supported. — M reas cn ca: 
70. They are hypogynous, when they are inserted on the receptacle; perigynous, 
when on the calyx ; epigynous, 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.). š 
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 
toward the petals. Occasionally, they are united into a tube (syngenesious). 
73. Between the stamens and the pistils is often a fleshy expansion, called the 
74. The Pistils occupy the centre of the flower. They 
in à whorl, on the receptacle; or, when this is elongated < 
