72 



COROLLA. 



Fig. 83. 



POLYPETALOUS COROLLA. 



of petals (from the Greek petalon, a leaf, 

 Jig. 83, c), and it is to be observed that 

 they differ from leaves more than the se'- 

 pals ; they have but few stomata ; their 

 nerves, which are similar to those of the 

 leaves as regards their direction, are 

 more slender, and contain no other kin'i 

 of vessels but tracheae ; they are very 

 seldom green, but generally possess the 

 most brilliant colours. 



29. The corolla is sometimes mono- 

 pe'talous or gamope'talous (Jig. 84), that 

 is, composed of a single piece, formed by the inti- 

 mate union of all the petals (as in the flower of the 

 bind-weed) ; at other times it is polypetalous (Jigs. 

 82, 83), that is, composed of a greater or less num- 

 ber of separate petals (as in the rose, pink, &c.). 

 The number of petals is ordinarily five, in which 

 case they are arranged around the essential or- 

 gans of the flower in a single row or whorl or 

 verticellus ; sometimes there are three or four 

 only, or seven, and at other times a much larger 

 number, and then they are placed so as to form 

 several concentric whorls (verticelli), and to alter- 

 nate with those of the neighbouring row. Polype'- 

 talous flowers are called dipe'talous when they 

 have two petals only ; tripe'talous when they have three ; tetra- 

 pe'talous, pentape'talous, hexape'talous, when they have four, five, 

 and six petals, and so on. 



30. We generally recognise in a pe'tal, the claw or inferior 

 part, corresponding to the petiole of the leaf, which is more or 

 less contracted, and the limb, which is more or less spread and 



Explanation of Fig. 82. A polypetalous flower (of the family of Rosa- 

 cese): a, the peduncle or flower-stalk ; 6,6,6,6, extremities of the divisions 

 of the calyx or sepals; cy, the petals of the corolla; rf, the stamens (in 

 this instance, perigy'novs, from the Greek, peri, around, and gune, woman), 

 in the midst of which is seen the pistil. 



Explanation of Fig. 83. Flower of a malva'cea : a, the calyx ; 6, the 

 corolla; c, the stamens united in a tubular andro'phorum (from the Greek 

 i/ner, man, or in Botany, a stamen, and pherein, to bear) a columnar ex- 

 pansion of the centre of the flower upon which the stamens seem to grow : 

 rf, the stigmata. 



Explanation of Fig. 84. Represents a monopetalous, labiate flower, or 

 lulobate corolla. 



29. What is meant by a monopetalous corolla ? What is a polypelaloua 

 corolla ? 



30. What is the claw of a petal ? What is the limb of a petal ? What 

 is the throat of a corolla ? 



Fig. 84. 



MONOPETALOUS 

 COROLLA. 



