432 BOTANY. 



penta-sepalous, etc. , and mono-, di-, tri-, tetra-, penta-petalous, etc., mean, 

 ing of one, two, three, four, five sepals or petals respectively. Polysepa- 

 lous and polypetalous are properly used to designate " a considerable but 

 unspecified number " of sepals or petals.* 



In some flowers the sepals or petals, or both, are united to one 

 another, so that the calyx and corolla are each in the form of a single 

 tube or cup. This union of similar parts is called coalescence. The 

 terms gamosepalous \ and gamopeta'ous (or sympetalous) are used in such 

 cases. Monosepalous and monopetalous, still used in this sense in many 

 descriptive works, sbould be reserved for designating the number of 

 sepals or petals in calyx and corolla respectively. 



Not infrequently the calyx and corolla are connately united to each 

 other for a less or greater distance. This union of dissimilar whorls is 

 termed adnation, aud the calyx and corolla are said to be adnate to 

 each other. 



The Andrcecium. The number of stamens in the flower or the 

 andrcecium is indicated by such terms as 



Monandroiis, signifying of one stamen ; 



Diandrous, of two stamens; 



Triandrous, of three stamens ; 



Tetrandrous, of four stamens when two of the stamens are longer 

 than the other two, the androecium is said to be didynamous; 



Pentandrous, of five stamens ; 



Htxandrous, of six stamens ; when four are longer than the remain- 

 ing two, the androecium is said to be tetradynamous. 



Other terms of similar construction are used, as heptandrous, seven 

 stamens ; octandrous, eight ; enneandrous, nine ; decandrous, ten ; dodec- 

 androus, twelve ; and polyandrous, many or an indefinite number of 

 stamens. 



The stamens may be in a single whorl (monocyclic), in which case, i f 

 agreeing in number with the rest of the flower, the andrcecium is said 

 to be isostemonous ; they are often in two whorls (bycydic), and when 

 each whorl agrees with the numerical plan of the flower, the andrce- 

 cium is diplostemonous. 



The various kinds of coalescence require the use of special terms. 

 When there is a coalescence of the filaments the andrcecium is 



Monadelphous, when the stamens are united into one set ; 



Diadelphous, when united into two sets ; 



Triadelphous, when united into three sets, etc. 



ous as it obviously is, has not yet been abandoned in works on descrip- 

 tive botany. 



* Dr. Gray throws the weight of his authority in favor of this use of 

 these terms (" Structural Botany," 1879, p. 244). 



\ From Greek ya/^oS, union. 



