''Crataegus collina'' is a type of

hawthorn Hawthorn or Hawthorns may refer to: Plants * '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae * ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...

that is closely related to ''C. punctata'', the dotted hawthorn, and sometimes considered to be the same species. A sample of ''C. collina'' and ''C. punctata'' has suggested that ''C. collina'' is

polyploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

, and ''C. punctata'' is

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

, but a wider sample is needed to confirm that this is generally the case.

References

collina Flora of the United States Taxa named by Alvan Wentworth Chapman {{Crataegus-stub