THE STAMENS 
78 
obdiploste?nonous (in two whorls, the outer opposite or anteposed to 
the petals, see Caryophyllaceae), haplo- or iso-stemonous (in one whorl, 
alternate to the corolla, or anteposed to it, as in Primulaceae), or in more 
than two whorls (Rosaceae). The stamens may be few and definite 
Fig. 6. Stamen Morphology. A, stamen with adnate anther from 
the front, B, the same from the back. C, stamen with versatile anther. 
D, tip of an anther with porous dehiscence. E, cross section of a ripe 
adnate anther to show pollen-sacs ; the two sacs in the right-hand lobe 
have just opened, a, anther, c , connective, d , line of dehiscence, f, 
filament, /, anther-lobe,/, pore, p.s. pollen-sac, v.b. vascular bundle. 
(usually under 20, often described as /non-, di-androtts , &c. according to 
the number) or indefinite (over 20, see Ranunculaceae, Rosaceae, &c.); 
they may be all free ( monandrons ,... polyandrous) or concrescent in 
1, 2, 3, many bundles ( mon -, di-, tri-, poly- adelphous) with free anthers, 
or including the anthers into one mass ( synandrous , noun synandrium) 
as in many Araceae, Cyclanthera, Phyllanthus sp., Cucurbitaceae, &c.; 
they may be concrescent also with the gynoeceum ( synandrous , Orchi- 
daceae), or have the anthers only united ( syngenesious, Compositae). 
There may be 2 stamens longer than the rest ( didynamous , Labiatae) or 
4 ( tetradyna/nous , Cruciferae). 
The anther may be sessile or on a filament ; may be joined to the 
filament by its whole length ( adnate , dorsifixed', A in Fig.), or by its 
base (innate, basifixed), or balanced on it, forming a T (versatile ; C) ; 
may be extrorse or introrse (opening away from, or towards, the centre 
of the flower). Its dehiscence may also be longitudinal (A) or trans- 
verse, valvular (by lids, Berberidaceae, Lauraceae), or by pores 
(Ericaceae, Gentianaceae, &c. ; D). The thecae may be twisted as in 
Columelliaceae, Cucurbitaceae, Cochliostema, &c. The pollen-sacs may 
be numerous, as in Viscum, &c., septate or chambered (Mimoseae, some 
Onagraceae, &c.). There may be appendages on the filaments (Zygo- 
phyllum, Amaryllidaceae, Hydrophyllaceae) or anthers (Ericaceae, 
