216 ESSENTIAL ORGANS — STAMENS. 



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 upon as caused by the non-appearance of an outer row 

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

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

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

 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.? 



When the stamens are under twenty they are called definite, and 

 the flower is oUgandrous {hXiyog, few, and av)]g, male or stamen) ; when 

 above twenty they are indefinite or polyandrous (jiroXijg, many), and are 

 represented by the symbol oo. The number of stamens is indicated 

 by the Greek numerals prefixed to the term androus ; a flower with 

 one stamen being monandrous (/ji,6mg, one) ; with two, diandrous (Sis, 

 twice) ; with three, triandrous (Tgiii, three) ; with four, tetrandrous 

 (riT^ag, four) ; with five, pentandrous {^itri, five) ; with six, hexan- 

 drous (e'5, six) ; with seven, heptandrous (ivrii,, seven) ; with eight, 

 octandrous (oKrii, eight) ; with nine, enneandrous (ivvsa, nine) ; with 

 ten, decandrous (dixa, ten) ; with twelve, dodecandrous (dude?ca, twelve). 

 These terms will be referred to when treating of the Linnsean system 

 of classification. 



A stamen consists of two parts — a contracted portion, usually 

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

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

 blade of the leaf, termed the anther (avSri^hg, belonging to a flower), 

 which contains a powdery matter, called pollm. 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 

 cannot perform its functions. The anther is developed before the 

 filament, and when the latter is not produced the anther is sessile 

 (sessilis, sitting), or has no stalk, as in the Mistleto. 



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, 

 which traverses its whole length, and terminates at the union between 

 the filament and the anther. The filaments of Callitriche verna are 

 said to have no vessels. The filament is usually, as its name imports, 

 filiform or thread-like, cylindrical, or slightly tapering towards its 

 summit. It is often, however, thickened, compressed, and flattened 

 in various ways. It sometimes assumes the appearance of a petal, 

 or becomes petaloid (viraXov, a leaf or petal, eI6og, form), as in 

 Canna, Maranta, Nymphsea alba (fig. 342) ; occasionally it is subulate 

 (subula, an awl), or slightly broadened at the base, and drawn out 



