Affanities
The petals are obcordate and emerginate, the stamens are inflexed in the bud, and the calyx attaches to the ovary wall. The corpophore is bifid, the commissure is slightly constricted, and the fruits are laterally or dorsally compressed, but they differ in size, shape, and indumentum. Due to the large number of species, Pimpinella ’s fruits might be elliptic, oblong, ovoid, cylindrical, or obovoid in form. The forms are ovoid, oblong, and ovoid-oblong because Psammogeton andAphanopleura have fewer species than other genera.
Psammogeton , Aphanopleura , and Pimpinella are the closely related genera that exhibit affinities with one another. In contrast to Aphanopleura and Psammogeton , which are annuals and Pimpinella L., Demavendia ,Haussknechtii , Zeraveschonia are perennials. The leaves ofPsammogeton and Aphanopleura species closely resemble to the genus Koulia , and all these three genera are annuals. Additionally, the new genus is closely related to Psammogeton by virtue of its thick root while as the root is considered as thin inAphanopleura . The fruits the genus Koulium progressively get narrower below and wider above that share some characters with the genus Pimpinella . The genus Koulium is allied toPsammogeton , Aphanopleura and Pimpinella but distinguished from them as in Table 1 and key below. The new genus is annual which is distinct from other genera being perennial such asDemavendia , Haussknechtii , Pimpinella andZeraveschonia . The study we conducted revealed thatAphanopleura and Psammogeton both retain 46 % of genus’ similarity with Koulium while as Pimpinella shares 30 %.