A few polyploid species as for example D. glochidiatus (2n = 4x = 44) and D. montanus (2n = 6x = 66) also exist.[28] [28] Cabbage (Brassica oleracea) 18 Broccoli, cabbage, kale, kohlrabi, brussels sprouts, and cauliflower are all the same species and have the same chromosome number.[21] [21] Citrus (Citrus x) 18 Chromosome number of the genus Citrus, which including lemons, oranges, grapefruit, pomelo and limes, is 2n = 18.[29] [30] Passion fruit (Passiflora edulis) 18 [31] Setaria viridis (Setaria viridis) 18 [32] Maize (Zea mays) 20 [21] Cannabis (Cannabis sativa) 20 Western clawed frog (Xenopus tropicalis) 20 [33] Australian pitcher plant (Cephalotus follicularis) 20 [34] Cacao (Theobroma cacao) 20 [35] Eucalyptus (Eucalyptus) 22 Although some contradictory cases have been reported, the large homogeneity of the chromosome number 2n = 22 is now known for 135 (33.5%) distinct species among genus Eucalyptus.[36] [37] Virginia opossum (Didelphis virginiana) 22 [38] Bean (Phaseolus sp.) 22 All species in the genus Phaseolus have the same chromosome number, including common bean (P. vulgaris), runner bean (P. coccineus), tepary bean (P. acutifolius) and lima bean (P. lunatus).[21] [21] Snail 24 Melon (Cucumis melo) 24 [39] Rice (Oryza sativa) 24 [21] Silverleaf nightshade (Solanum elaeagnifolium) 24 [40] Sweet chestnut (Castanea sativa) 24 [41] Tomato (Solanum lycopersicum) 24 [42] European beech (Fagus sylvatica) 24 [43] Bittersweet nightshade (Solanum dulcamara) 24 [44][45] Cork oak (Quercus suber) 24 [46] Edible frog (Pelophylax kl. esculentus) 26 Edible frog is the fertile hybrid of the pool frog and the marsh frog.[47] [48] Axolotl (Ambystoma mexicanum) 28 [49] Bed bug (Cimex lectularius) 29–47 26 autosomes and varying number of the sex chromosomes from three (X1X2Y) to 21 (X1X2Y+18 extra Xs).[50] [50] Pill millipede (Arthrosphaera magna attems) 30 [51] Giraffe (Giraffa camelopardalis) 30 [52] American mink (Neovison vison) 30 Pistachio (Pistacia vera) 30 [53] Yeast (Saccharomyces cerivisiae) 32 European honey bee (Apis mellifera) 32/16 32 for females (2n = 32), males are haploid and thus have 16 (1n =16).[54] [54] American badger (Taxidea taxus) 32 Alfalfa (Medicago sativa) 32 Cultivated alfalfa is tetraploid, with 2n=4x=32.