GLOSSARY OF BOTANICAL TERMS 311 



Cross-fertilisation, the act of impregnation of the egg or ovum 

 of one flower by the male gamete (q.v.) of another 

 flower (pp. 52, 268). 



Cross-pollination, the dusting of the stigma of one flower by 

 the pollen brought from another (p. 268). 



Crustaceous, forming a crust, closely adherent to the sub- 

 stratum e.g., Crustaceous Lichens (p. 292). 



Cyclic, a term applied to leaves or parts of a flower arranged in 

 whorls; cf. Acyclic. 



Cyme, a form of inflorescence in which the main axis ends in a 

 flower, and the succeeding flowers are produced on succes- 

 sive, lateral axes. A cyme is also called a centrifugal 

 inflorescence, because the oldest flower is placed centrally 

 e.g. 9 Lychnis (p. 225). 



Deciduous, applied to those plants whose leaves do not persist 

 from year to year (cf. Evergreen), but are shed each 

 autumn. 



Decurrent, applied to leaves which are prolonged downwards 

 on the axis e.g., leaves of Thistles. 



Dehiscent, opening at one or more points so as to allow the 

 contents to escape. Applied to fruits and pollen sacs. 



Dichasium, a form of cyme, in which two lateral branches of 

 nearly equal strength arise below the flower which 

 terminates the main axis. These lateral branches may 

 each again give rise to two branches, and so on. 



Dichogamous, a term applied to flowers in which the stamens 

 and carpels ripen at different times, and thus self-pollina- 

 tion is prevented. 



Dicotyledon, a plant having two seed-leaves. The Dicoty- 

 ledons form the majority of the flowering plants; cf. 

 Monocotyledon. 



Dioecious, unisexual male and female flowers borne on different 

 plants (p. 189). 



Dimorphism = Heterostylism, flowers of two or more forms 



