xxx BOTANY. 
longer than the other two, the andracium is said to be didyna- 
mous (Fig. XXIV); 
Pentandrous, of five stamens; 
Hexundrous, of six stamens; when four are longer than the re- 
maining two, the andreecium is said to be tetradynamous. (Fig. 
XXYV.) 
Other terms of similar construction are used, as heptandrons, 
seven stamens; octandrous, eight; enneandrous, nine; decandrous, 
ten; dodecundrous, twelve; and polyandrous, many or an indefinite 
number of stamens. 
Fie. XXIV. 
Fie. XXVI. 
Fic. XX1V.—Tetrandrous flower; stamens didynamous. 
Fie, XXV.—Hexandrous flower; stamens tetradynamous. 
Fie. XXVI.—Bicyclic androecium, 
The stamens may be in a single whorl (sewryelic), in which 
case, if agreeing in number with the rest of the flower, the an- 
dreecium is said to be isostemonous; they are often in two whorls 
(bicyclic, Fig. XXVI), and when each whorl agrees with the 
numerical plan of the flower, the andreecium is diplostemonous. 
Union of Stamens.—The various kinds of union require the use 
of special terms. When there is a union of the filaments the an- 
dreecium is 
Monadelphous, when the stamens are united into one set (Fig. 
XXVID; 
Diadelphous, when united into two sets (Fig. XXVIID; 
Triadelphous, when united into three sets, etc. (Fig. XXIX) 
When there is a union of the anthers the andiecium is syngene- 
sious or synantherous. 
Adnation of Stamens, —-The stamens may be adnate to the petals, 
when they are epipetalvus ; in some cases they are adnate to the 
