The diploid (2n) hybrid between these two species is sterile because the nine C. epilobioides chromosomes and the nine C. unguiculata chromosomes are not truly homologous; therefore, the chromosomes fail to pair up properly during synapsis of Meiosis I. A naturally-occurring, fertile, tetraploid hybrid with four sets of chromosomes (two from each parent) gave rise to a new breeding population of C. delicata, which is considered to be a separate species. The hybrid has 18 chromosomes in its gametes (egg and sperm) and 36 chromosomes in the cells of the sporophyte. The petals lack the long stalk (claw) of C. unguiculata and are somewhat intermediate between the two parents. By the way, clawed mammals are referred to as unguiculates (mammals with hoofs are called ungulates), but in botany the term claw refers to the slender stalk of a petal.