ESSENTIAL ORGANS. STAMENS. 189 



are normally developed, and are more numerous than the sepals and 

 petals, they will be found arranged in several whorls, and their parts 

 multiples of the floral envelopes. Thus, if a flower has five sepals, five 

 petals, and twenty stamens, the latter are arranged in four alternate 

 rows, having five in each. Although this is the usual law, yet various 

 changes take place by abortion and arrestment of development. In 

 this way the stamens may neither be equal to, nor a multiple of, the 

 floral envelopes, and they may even be less numerous, so that the flower 

 is miostemonous (/uiiav, less). 



393. In certain cases, as in Primula, the row of stamens is opposite 

 to the petals forming the gamopetalous corolla. This opposition is by 

 many looked xipon as caused by the non-appearance of an outer row 

 of stamens; by others it is considered as produced by chorization or 

 separation of lamina? from the petals, which become altered so as to 

 form stamens, a view which is thought to be confirmed by their de- 

 velopment taking place before the petals; by a third party, each petal 

 is looked upon when fully developed as formed by the halves of two 

 contiguous petals, and thus the stamens are considered as being really 

 alternate with the original petals. 



394. When the stamens are under twenty, they are called definite, 

 and the flower is oligandrous (o'A/yo?, few, and eivyp, male or stamen); 

 when above twenty, they are indefinite or polyandrous (VoAi)f, many), 

 and are marked ><>. The number of stamens is indicated by the Greek 

 numerals prefixed to the term androus: a flower with one stamen be- 

 ing monandrous (povog, one); with two, diandrous (S/V, twice); with 

 three, triandrous (r^i7;, three); with four, tetrandrous (rsr^x;, four); 

 with five, pentandrous (vivrs, five); with six, hexandrom (I|, six); with 

 seven, heptandrous (kvr*, seven); with eight, octandroits (6x.ru, eight); 

 with nine, enneandrous (sweat, nine); with ten, decandrous (btx.*., ten); 

 with twelve, dodecandrous (3<y3gK, twelve). These terms will be 

 referred to when treating of the Linnasan system of classification. 



395. A stamen consists of two parts a contracted portion, usually 

 thread-like, equivalent to the petiole of the leaf, and termed the fila- 

 ment (jilum, a thread); and a broader portion, representing the folded 

 blade of the leaf, termed the anther (dvfagci;, belonging to a flower), 

 which contains a powdery matter, called pollen. The filament is no 

 more essential to the stamen than the petiole is to the leaf, or the claw 

 to the petal. If the anther is absent, the stamen is abortive, and can- 

 not perform its functions. The anther is developed before the fila- 

 ment, and when the latter is not produced the anther is sessile (sessilis, 

 sitting), or has no stalk, as in the Misletoe. 



396. The Filament, when structurally considered, is found to consist 

 of a thin epidermis, on which occasionally stomata and hairs occur, 

 and of a layer of cellular tissue enclosing a bundle of spiral vessels, 



