Trees of New York State 35 



II. Determinate inflorescence. Axis of inflorescence termin- 

 ated by a flower which prevents further elongation of the pri- 

 mary axis. Represented by but one type with various modi- 

 fications, the cyme. (Fig. 43.) 



III. Mixed inflorescence. Said of an inflorescence in which 

 both indeterminate and determinate types of branching are 

 found ; ])rimary branching of one type, secondary branching of 

 another type; rare in trees. 



FLOWERS 



General 



Flowers are structures characteristic of the Spermatophytes 

 or seed plants and bear stamens and ovules or immature seeds. 

 In Gymnosperms these ovules are not enclosed in an ovary but 

 are borne naked or in the axils of cone scales, and the flowers are 

 devoid of perianth, while in the Angiosperms an ovary is always 

 present and is usually accompanied by a more or less showy peri- 

 anth. The function of flowers is that of seed production and the 

 various floral parts, included under the terms perianth and essen- 

 tial organs, are to be considered as modified leaves. The parts of 

 a typical flower are as follows (see Fig. 47) : 



Floral Parts 



I. Pedicel or peduncle. Stalk of flower. 

 11. Receptacle. End of peduncle bearing the remaining parts, 

 usually somewhat enlarged. 



III. Perianth. The outer .sets of modified leaves composing the 



non-essential part of the flower. 



a. Calyx. The outer set, consisting of sepals, usually 



green in color. 



b. Corolla. The inner set, consisting of petals, usually 



showy in color. 



IV. Essential organs. Stamens and pistil. 



a. Andrv)ecium. The outer set of essential organs, the 



stamens, each consisting of an anther or pollen- 

 bearing portion, borne on a stalk or filament. 



b. Gynoecium. The inner set of essential organs, the 



carpels, which unite to form a pistil. A pistil con- 

 sists of (1) an enlarged basal part bearing ovules, 

 (2) a slender stalk above, the style,* and (3) a ter- 

 minal portion, receptive to pollen, the stigma. 



style may or may not be present. 



