Definitions. xxxv 



distinguishable from the top of the style. So also it is often difficult 

 for those who do not use a microscope to determine whether there is 

 one style with several branches or several distinct styles, and whether 

 one style has several stigmas or one stigma branched or lobed. 



35. The placenta is the part of the inside of the ovary to which 

 the ovules, which are the first germs of the future seeds, are attached. 

 In all works of scientific botany the nature of the placenta and the 

 position of the ovules are made much of, but these being mainly 

 microscopical details, do not come within the scope of this work. 



The main parts of the perfect flower having been described, some 

 less important details have to be mentioned before the fruit is con- 

 sidered. 



36. The stalk of the flower is called the pedicel ; when a number of 

 flowers are aggregated the common stalk is called the peduncle, each 

 separate flower (unless sessile) having its own pedicel. 1 The 

 extremity of the pedicel on which the corolla and ovary (and some- 

 times the stamens) are inserted is called the receptacle, thalamus, or 

 torus. It is often not sufficiently enlarged to be readily noticed. The 

 disk is a more or less circular enlargement of the receptacle, and may 

 be entire, cut, or divided. It is always inside the calyx. When the 

 parts of the disk are quite separate they are often called glands. In 

 many of the orders of division Disciflorce, the disk is very con- 

 spicuous, but in very many plants it is either absent or minute. 



37. Bracts are leaf-like appendages to the flower, much as stipules 

 are to leaves ; they very often resemble the sepals in size and shape. 

 Their most usual position is at the base of the flower, but sometimes 

 they are on the pedicel or the main stem. There are sometimes 

 larger bracts at the base of the pedicel and smaller ones at the 

 base of the flower ; these latter are then called bracteoles. When a 

 number of bracts are united in a whorl they are called an involucre, 

 a number of bracteoles similarly united an involucel. (See orders 

 Malvaceae, Umbelliferce, and Acanthacece.') Bracts or other parts of the 

 flower when from the first dry and withered looking are called 

 s carious. 



38. The way in which the separate flowers are arranged is called 

 the inflorescence of the plant. If the flowers occur one by one they 

 are said to be solitary, if two together twin. A number of sessile 

 flowers arranged round a stem or branch is called a whorl (see order 

 Labiatae) ; collected into a round or oval cluster, a head; arranged on or 

 round one main peduncle one above the other, a spike. 



39. A number of stalked flowers arranged on or round a main 

 peduncle one above the other is a raceme, arranged on a branched 

 peduncle, a panicle. A panicle is dichotomous when each branch 

 forks into two, and the same forking occurs again and again ; 

 trichotomous when each branch forks into three. When several 

 branches or pedicels of the same length start from the same 

 point of the peduncle (radiating like the ribs of an umbrella), the 

 inflorescence is an umbel. (See order Umbellifcrae ) The t^rms cyme 



1 When a flower is solitary its stalk is often called peduncle or 

 pedicel indifferently. 



