RUDIMENTS OF BOTANY. XI 



FLOWER-BUDS. 



50. The flower-bud consists of imbricated rudimentary or metamorphosed 

 leaves, the external or inferior of which are usually alternate, and the in- 

 ternal or superior always verticillute or opposite ; the latter are called floral 

 envelopes and reproductive organs. 



51. The leaves, from the axils of which the flower-buds arise are called 

 bracts or floral leaves; and those leaves which appear on the pedicel between 

 the bracts and calyx, are called bracteoles. These, although essentially 

 distinct, are often confounded with the former. 



52. When a single bract is rolled together, highly developed, and colored, 

 and is placed at the base of the form of inflorescence called a spadix, it is 

 named a spalhe* 



53. When several bracts are verticillate or densely imbricated around the 

 base of the forms of inflorescence called the umbel or head, they are termed 

 an involucre ; and those at the base of each partial umbel, are called in- 



rolucels. 



54. Small imbricated bracts are often called scales; as in the Com- 

 positae. 



55. Bracts, when placed immediately below the stamens and pistils, as in 

 apetalous flowers, are only distinguished from the calyx by being alternate 

 with each other, and not verticillate ; hence the glumes and palea of grasses 

 are bracts, and not calyces. 



56. The elongation of the axis of the flower-bud from the point of its 

 connection with the stem, as far as the floral envelopes, is called the pe- 

 duncle. 



57. When several peduncles spring from the axis near to each other, the 

 axis is termed a rachis, and the peduncles themselves are called pedicels. 



58. Those axes which spring from the earth and bear no true leaves, are 

 denominated scapes. 



59. The modes in which the flower-buds are arranged are called forms if 

 inflorescence ; and the order in which they unfold, is called the order of e-. 

 pansion. 



INFLORESCENCE. 



60. When a flower-bud gives rise to only one flower, terminal on its pe- 

 duncle, and the axis of the plant does not elongate beyond the bud. the 

 flower is commonly said to be terminal and solitary. 



61. When the axis, however, continues to elongate and the bract retains 

 the form and size of a leaf, the flower is termed axillary and solitary. 



62. If the buds instead of giving rise to one terminal flower have the axis 

 elongated, bearing several flowers, and each flower on a peduncle, a raceme 

 is formed. 



63. When each flower is sessile or placed in the axil of the bracts, with- 

 out a peduncle, a spike is produced. Hence the only difference between a 

 spike and raceme is, that in the former the flowers are sessile and the lat- 

 ter stalked. The term spike, however, is applied in those cases where the 

 peduncle is scarcely perceptible. 



64. A spadix is a sort of spike, in which the flowers are closely packed 

 together upon a succulent axis, which is enveloped in a spathe. 



