Fig. 260. A small Passion-flower, with crown of slender threads.
262. Such petals, and various others, may have an outgrowth of the inner face into an appendage or fringe, as in Soapwort, and in Silene (Fig. [259]), where it is at the junction of claw and blade. This is called a Crown, or Corona. In Passion-flowers (Fig. [260]) the crown consists of numerous threads on the base of each petal.
Fig. 261. Front view of a papilionaceous corolla. 262. The parts of the same, displayed: s, Standard, or Vexillum; w, Wings, or Alæ; k, Keel, or Carina.
[263.] Irregular Flowers may be polypetalous, or nearly so, as in the papilionaceous corolla; but most of them are irregular through coalescence, which often much disguises the numerical symmetry also. As affecting the corolla the following forms have received particular names:
[264.] Papilionaceous Corolla, Fig. [261, 262]. This is polypetalous, except that two of the petals cohere, usually but slightly. It belongs only to the Leguminous or Pulse family. The name means butterfly-like; but the likeness is hardly obvious. The names of the five petals of the papilionaceous corolla are curiously incongruous. They are,
The Standard or Banner (Vexillum), the large upper petal which is external in the bud and wrapped around the others.