INTRODUCTION TO BRITISH BOTANY 



The most common forms of the regular corolla of one petal are ; 



Salver-shaped, as in Primrose, Plate 74. 



Funnel-shaped, as in Cowslip, Plate 74. 



Wheel-shaped, when the tube is no longer in proportion than the 

 axle of a wheel, as in Speedwell, Plate 69. 



Bell-shaped, as in Campanula, p. 384. 



Trumpet-shaped, as in Convolvulus, Plate 57. 



When the irregular corolla of one petal is divided into two lobes, 

 one of which overhangs the other, it is termed labiate, or lipped, as 

 in the Natural Family Labiata? ; if the lips are open, it is said to be 

 gaping, as in Yellow Dead Nettle ; if closed, personate, (from 

 persona, a mask), as in Toadflax. In the Compound Flowers, 

 p. 146, there are frequently two kinds of florets in one flower ; 

 those of the disk, or centre, being tubular, without an evident 

 border ; those of the ray, or margin, strap-shaped, as in the Daisy. 



Among regular flowers of many petals, the only form which it 

 will be necessary to mention here is the cruciform, consisting of four 

 petals placed cross-wise, as in the Cruciferous Tribe, p. 16. 



The most remarkable among the irregular is the papilionaceous, 

 (from papilio, a butterfly), consisting of five petals, of which the 

 upper one, called the standard, is usually the largest ; the two side 

 ones are termed wings, and the two lower ones, which are often 

 combined, form the keel, p. 62. 



Both calyx and corolla are not always found in the same flower, 

 and when one only is present, it is sometimes difficult to decide by 

 what name it should be called. In this case the term perianth 

 (from the Greek peri, around, and anthos, a flower) is a convenient 

 one. Some flowers have neither calyx nor corolla, as Water Star- 

 wort. When the perianth is said to be double, it is to be understood 

 that calyx and corolla are both present. 



The Stamens. Within the perianth, and frequently attached to 

 it, is a row of delicate organs called stamens, of which the lower part 

 is termed the filament, the upper the anther. When 

 the filament is slender throughout, it is said to be 

 thread-like ; but if it be thick at the base, and taper 

 to a point, it is said to be awl-shaped. The anther 

 varies in shape, but is most frequently oblong, and 

 composed of two lobes and as many cells, which are 

 rilled with a fine dust, called pollen. If there be no filament, 

 the anther is said to be sessile. In a majority of flowers the 

 number of stamens equals that of the petals ; a few plants have 

 but one stamen : very often the number of stamens is some mul- 

 tiple of the petals that is, there are twice or thrice, etc., as many, 

 and not a few flowers have from twenty to several hundred. Some- 

 times the filaments are united at the base into one or more sets, 

 as in Hypericum, p. 52 : sometimes they form a hollow tube, the 



