226 ESSENTIAL ORGANS — STAMKNS. 



two, and Poranthera (fig. 355), where there are four. In Tetratheca 

 juncea the four cavities (fig. 356, 2) open into a single pore at the apex 

 (fig. 356, 1) ; and in the Mistleto the anther has numerous pores for 

 the discharge of the pollen. Another mode of dehiscence is called 

 hinged. In the Barberry each lobe opens by a valve on the outer 

 side of the suture, separately rolling up from base to apex ; while in 

 some of the Laurel tribe (fig. 357 v) there are two such separating 

 valves for each lobe, or four in all. This may be called a combination 

 of transverse and hinged dehiscence. In some Guttiferse, as Hebra- 

 dendron cambogioides (the Ceylon Gamboge plant), the anther opens 

 by a lid separating frorh the apex, or as it is called circumscissile 

 (circum, around, scindo, I cut) dehiscence. In the last-mentioned 

 dehiscence the anther may be considered as formed of jointed leaves 

 like those of the Orange, the blades of which separate at the joint. 



The anthers open at different periods during the process of flowering ; 

 sometimes in the bud, but more commonly when the pistil is fully de- 

 veloped, and the flower is expanded. They either open simultaneously 

 or in succession. In the latter case, individual stamens may move in 

 succession towards the pistil and discharge their contents, as in Pamassia 

 palustris, or the outer or the inner stamens may open first, following 

 thus a centripetal or centrifugal order. The anthers 

 are called introrse {introrsum, inwardly), or anticce 

 (anticus, the fore part), when they open on the sur- 

 face next to the centre of the flower (fig. 377) ; they are 

 extrorse (extrorsum, outwardly), ot posticx (posticus, be- 

 hind), when they open on the outer surface ; when they 

 open on the sides, as in Iris, and some grasses, they 

 are' called laterally dehiscent (fig. 369). Sometimes 

 ■ anthers, originally introrse, from their versatile nature 

 become extrorse, as in the Passion-flower and Oxalis. 

 The attachment of the filament either on the outer 

 or inner side, and the position of the anther in the 

 young state, assist in determining the direction of the dehiscence when 

 the anthers open by pores, or are versatile. 



The usual colour of anthers is yellow, but they present a great 

 variety in this respect. The are red in the Peach, dark purple in the 

 Poppy and Tulip, orange in Eschscholtzia, etc. The colour and appear- 

 ance of the anthers often change after they have discharged their 

 functions. 



Sometimes a flower consists of a single stamen, as already stated 

 in regard to Euphorbia. It is said, also, that in the Coniferse, as in 



Fig. 377. Tetradynamous stamens (two long and two short) of Cheiranthus Cheiri. p. Top 

 of the peduncle, c. Cicatrices left by the sepals of calyx which have been removed, eg, Two 

 pairs of long stamens, ep. The short stamens, t, Torus or thalamus to which the stamens 

 are attached. 



