70 THE FLOWER ( CONCRESCENCE ) 
oligomerous , with more members, pleomerous). Flower with 2, 3, 4, 5 
whorls di-, tri tetra-, penta- cyclic ; with 2, 3, 4, 5 members in each 
whorl di -, iri-, tetra -, penta-merous. The number of organs in each 
whorl is given if the flower is heteromerous ; if over 10 and variable 
it is usually termed indefinite , e.g. stamens and carpels of Ranunculus. 
Members of one whorl are usually alternate to those of the next outer 
whorl, but may be opposite ( superposed , anteposed) to them ; this is 
usually described as ‘ Stamens antepetalous ’ and so on (see stamens, 
below, and diagrams of Caryophyllaceae, Primulaceae). 
Concrescence (p. 30) of organs is a common and 
important phenomenon. When it takes place between 
similar organs, e.g. in the corolla of the Sympetalae, it is 
commonly termed cohesion , when between dissimilar organs, 
e.g. between stamens and petals, as in thyme or mint, 
adhesion . The latter rarely occurs without the former. 
Concrescence of sporophylls, especially of carpels, probably 
effects great economy in fertilisation, by making only one 
track for the pollen-tubes to all the ovules ; in the perianth 
it often saves material and helps to narrow the entrance to 
the honey (see below). 
Descriptive Terms. Perianth, calyx, corolla, stamens, carpels, of 
organs free from one another, polyphyllous , polysepalous, polypetalous, 
polyandrous , apocarpous; of concrescent (‘coherent’) organs, gamo- 
phyllous , ga? 7 iosepalous , ga?no- or sym-petalous , ?nonadelphous (if all 
stamens concrescent ; see below under stamens), syncarpous. Stamens 
concrescent with (‘adherent to’) carpels, corolla, calyx, perianth, 
gynandrous , epipetalous , episepalous , epiphyllous. The concrescent por- 
tion is termed the tube , the free part the limb ; the latter is divided 
into lobes 1 teeth , or segffients. 
Multiplication of organs, or the presence of more than 
one in a place where comparison (p. 27) shows that there 
was probably only one in an ancestral form, is not infrequent. 
It is usually due to branching ( chorisis , dedoubletnent ), and is 
especially common in stamens, e.g. in some Myrtaceae 
(Calothamnus, &c.), Papaveraceae (Fumaria, &c.), Ricinus, 
Polygonaceae, Malvaceae, Cruciferae, Capparidaceae, Gutti- 
ferae, &c. It occurs in the carpels of Nolanaceae and many 
Malvaceae, &c. 
Abortion and Suppression (p. 31) are also common. 
Reduction of number of sporophylls and oligomery of the 
carpels are mentioned above. Abortion is very common in 
stamens, small functionless staminodes being left, e.g. in 
Scrophularia ; it also occurs in the petals of Aconitum, the 
