| In the first and original family, the Zygospyrida, the shell is represented by the bilocular cephalis only. |
| The ovary is bilocular with single ovule per locule and the placentation is axile. |
| Meanwhile, Pyrostria group B shares characters with Pyrostria group A in having unisexual flowers, bilocular ovaries, broad corolla tube, and 4-5 corolobesobut buthehe former radiates as far as SE Asia. |
| Anthers inserted near the apex of the tube, short, fleshy, bilocular. |
| They are always benign and are characterised by unilocular or bilocular cysts that are greater than 2 cm in size. |
