PLANT ORGANS AND~ORGANISMS 183 
When the staminate and pistillate flowers are borne on different 
plants of the same species, they are termed Dioecious, as the Sassafras 
and Willow. When staminate, pistillate and hermaphrodite flowers 
are all borne on one plant, as on the Maple trees, they are polygamous. 
Connation and Adnation.—In the development of the flowers of 
primitive species of flowering plants, the parts of each whorl are dis¬ 
joined or separate from each other. In many higher types, however, 
the parts of the same whorl frequently become partly or completely 
united laterally. This condition is termed connation, coalescence, 
cohesion or syngenesis. Illustrations of this may be seen in Bella¬ 
donna, Stramonium and Uva Ursi flowers, where the petals have 
joined laterally to form gamopetalous corollas. When the one or 
more parts of different whorls are united, as of stamens with petals 
(Rhammus) or stamens with carpels (Apocynum) the union is called 
adnation or adhesion. 
The Receptacle.—The Receptacle, Torus or Thalamus is a more or 
less. shortened axis (branch) which bears the floral leaves. It is 
usually flat or convex, but may be conical and fleshy as in the Straw¬ 
berry, concave as in the Rose and Fig or show a disc-like modifica¬ 
tion as in the Orange. The internodes of the receptacle in many 
species lengthen and separate various whorls. When the lengthen¬ 
ing of the internode occurs between calyx and corolla, as in Lychnis, 
the structure resulting is called an anthophore', if between corolla and 
androecium as in Passiflora, a gonophore ; if betwen androoecium and 
gynoecium as in Geum, a gynophore. If the flowers of the Umbel - 
liferoe the receptacle elongates between the carpels producing the 
structure called a carpophore. 
The Perigone.—The perigone or perianth is the flo'ral envelope 
consisting of calyx And corolla (when present). 
When both whorls, i.e., calyx and corolla, are present the flower is 
said to be dichlamydeous', if qnly calyx is present, monochalmydeous. 
The Calyx.—The Calyx is the outer whorl of modified leaves. Its 
parts are called Sepals, and may be distinct (Chorisepalous, from a 
Greek word meaning disjoined) or more or less united (Gamosep- 
alous). They are usually green—foliaceous or leaf-like—but may 
be brilliantly colored, hence the term petaloid (like the petals) is 
applied. Examples: Tulip, Larkspur, Columbine and Aconite. 
