The non-articulate tissue which occurs in Euphorbiaceae, Apocynaceae, Urticaceae, Asclepiadaceae, consists of long tubes, equivalent to single multinucleate cells, which ramify in all directions throughout the plant.
C. Pinch-trap flowers, as in the family Asclepiadaceae, where the proboscis, claw or bristle of the insect is caught in the clip to which the pairs of pollinia are attached.
Filaments sometimes are adherent to the pistil, forming a column (gynostemium), as in Stylidium, Asclepiadaceae, Rafflesia, and Aristolochiaceae (fig.
In Asclepiadaceae the pollinia are usually united in pairs (fig.
The union is usually most complete at the base; but in Labiatae the styles are united throughout their length, and in Apocynaceae and Asclepiadaceae the stigmas only.
In Asclepiadaceae the stigmas are united to the face of the anthers, and along with them form a solid mass.