Mahinda Martínez. A genetic study by Whitson and Manos in 2005 found evidence that supports the Physalodendron and Rydbergis subgenera. The same research indicated that evidence was weak for most of the recognized species sections within the Rydbergis subgenus, but that other subgroupings might be appropriate instead. This and other phylogenic research led to the Whitson proposal in 2016 to establish Alkekengi officinarum as the type of a new genus rather than the type species of Physalis. Genetics and breeding The basic number for Physalis species is 12, and most Physalis species are diploid with 2n = 24. This basic number is typical for members of the Solanaceae family. Research has identified several species that have experienced polyploidy, including Physalis angulata, Physalis floridana, Physalis pubescens, and Physalis peruvania. Physalis species are generally self-compatible and autogamous, although some may exhibit self-incompatibility and require pollen from another plant to bear fruit or produce seed. A study in 2022 found self-compatibility for all seven Physalis that were observed, which included Physalis peruviana and Physalis ixocarpa. The same study found that fruit fixation and viable seed formation occurred in most inter-specific crosses. The authors did not grow offspring to the second generation. Menzel performed crosses between Physalis species to assess hybridization in 1951 which showed that perennial species are prone to hybridization while annual Physalis species exhibited barriers between crossing. Hinton identified natural hybridization events between Physalis virginiana Mill. and Physalis heterophylla Nees, which Hinton hypothesized could be the result of self-incompatibility and lack of Physalis virginiana pollen. Sullivan reported in 1985 that natural hybridization rarely occurs among four species from the Physalis viscosa complex. Physalis subgenus Physalodendron Authority: (G. Don) M. Martinez Physalis arborescens Physalis melanocystis Physalis subgenus Rydbergis Authority: Hendrych Section Angulatae Authority: (Rydberg) M. Martinez Physalis acutifolia (Miers) Sandw. – sharp-leaved groundcherry, Wright groundcherry Physalis ampla Waterfall Physalis angulata L. – cut-leaved groundcherry, lance-leaved groundcherry, camapu Physalis carnosa Standley Physalis crassifolia Benth. – thick-leaved groundcherry, yellow nightshade groundcherry Physalis ixocarpa Brot – tomatillo Physalis lagascae Roem. & Schult. Physalis microcarpa Urb. & Eckman Physalis minima Linneaus – pygmy groundcherry, native gooseberry (Australia) Physalis philadelphica Lam. – tomatillo, Mexican groundcherry, jamberry, Mexican tomato, tomate de cáscara, tomate de fresadilla, tomate milpero, tomate verde Physalis solanacea (Schlechtendal) Axelius Physalis sulphurea (Fernald) Waterfall Section Campanulae Authority: M. Martinez Physalis campanula Standl. & Steyerm. Physalis glutinosa Schltdl. Section Coztomatae Authority: M. Martinez Physalis aggregata Waterfall