78 



STAMENS. 



.Fig. 100. 



Fig. 101. 



DIANDROUS. 



40. The number of stamens varies much in different plants ; 

 certain flowers which are on this account named monandrous 



(from the Greek, monos, single, and 

 aner, stamen), have but one stamen ; 

 other flowers called diandrous (Jig. 

 101), triandrous, tetrandrous, pen- 

 tandrous, &c. (Jig. 100) have two, 

 three, four, five, or more stamens. 

 In general, their number is equal to 

 that of the petals, or is a multiple of 

 tne peta}s. Sometimes they are all 

 alike, and at other times they are not of the same 



size ; when the same flower always has two short and two long 



stamens, it is named didyna'mous (from the Greek, dis t twice, 



and dunamis, power) ; when the whole 



number of stamens is six, and four of 



them are longer than the other two, the 



plant is termed tetradyna'mous (from the 



Greek, teteres, four, arid dunamis, power). 



These organs form one or more whorls 



or verlicels, situate within the corolla 



(jig" 102), and in general those which 



form the external whorl (or the only ,.,. 



verticel when there is but one) regularly '^' 



alternate with the petals, so that each stamen corresponds with 



one of the divisions of the corolla. 



41. Each stamen consists of three parts: namely, the Jila- 

 ment, the anther ', and the pollen. 



42. The ' Jilament of a stamen is a sup- ? 

 port analogous to the petiole of the leaves 



and the claw of the petals, and is gene- 

 rally cylindrical and slender, as in fig. b - 

 103, b. Sometimes it is so short that 

 it seems to be wanting, and in this case, 

 the stamen is said to be sessile; gene- 

 rally, however, it is very long. 



43. The filaments arise from the 



Fig. 103. STAMENS. 



Explanation of Fig. 103. A flower without its envelopes ; cr, the calyx ; 

 fe, the filament of the stamen ; c, the anthers ; (7, the ovary ; e, the 

 stigma. 



40. Have all flowers the same number of stamens ? What is a didy- 

 na'mous flower? What is a tetradyna'mous flower? How are sta'mens 

 placed in respect to the petals ? 



41. Of what parts does each stamen consist ? 



42. What is the filament ? When is a stamen said to be sessile ? 



43. What part gives rise to the filament? Are the filaments joined 

 together, or are they separate from each other ? What is an androphor ? 



