192 



ESSENTIAL ORGANS. STAMENS. 



dies may be equal or unequal. It frequently happens, especially in 

 Papilionaceous flowers, that out of ten stamens, nine are united by 

 their filaments, while one (the posterior one) is 

 free. When filaments form three or more bun- 

 dles, the stamens are triadelphous (TJ<?, three), 

 as in Hypericum segyptiacum (fig. 315), or polya- 

 delphous (-s-oXiyf, many), as in Luhea paniculata 

 (fig. 316, 1), or in Ricinus communis (fig. 317, 

 1). The union of the filaments takes place some- 

 times at the base only, as in Tamarix gallica (fig. 

 311); at other times it extends throughout their 

 Avhole length, so that the bundles assume a 

 columnar form. In certain cases, the cohesion 

 extends to near the apex, forming what Mirbel 

 calls an androphore (K.V/JQ, male or stamen, and 

 (?>o(>fa, I bear), or a column which divides into terminal branches, each 

 bearing an anther (fig. 315, fe). Occasionally some filaments are 

 united higher up than others, and thus a kind of compound branching 

 is produced (fig. 317, 2). In Pancratium, the filaments are united by 

 a membrane, which may be considered as corresponding to the crown 

 of Narcissus. 



316, 1 



316, 2 



317, 2 



317, 1 



400. Filaments sometimes are united with the pistil, forming a 

 columna or column, as in Stylidium, Asclepiadacea?, Eafflesia, and Or- 

 chidaceae. The column is called gynostemium ("/My, pistil, and ar^av, 

 stamen), and the flowers are denominated gynandrous (yt/j/jj, pistil, and 

 male or stamen). 



Fig. 315. Triadelphons stamens of Hypericum aegyptiacutn surrounding the pistil, o. //, 

 United filaments forming columns, e e, Anthers, free. The outer envelope .of the flower has 

 been removed, the essential organs alone heing left 



Fig. 316. 1. Flower of Luhea paniculata. c c c c, Segments of calyx, p p, Petals, e e, Sta- 

 mens grouped in bundles, which alternate with the petals, s, Stigma, composed of five parts, 

 indicating the union of five carpels. 2. One of the staminal bundles magnified, showing all the 

 filaments united into a single mass at the base, but separating superiorly, fa, The larger in- 

 ternal filaments, each ending in an anther. /, The shorter outer ones, sterile and abortive. 



Fig. 317. 1. Male flower of Ricinus communis, or Castor oil plant, consisting of a calyx, r, 

 composed of five reflexed sepals, and of stamens, e, united by their filaments so as to form many 

 bundles, thus being polyadelphous. 2. One of the stamiual bundles, /, branching above, so as to 

 leave the anthers free and separate. 



