Using a technique known as flow cytometry, scientists can measure the amount of DNA within the nucleus of a cell. This, in turn, is helpful to determine the ploidy of hosta cultivars and species. In addition, DNA testing can identify ploidy chimeras that have different ploidy among the three apical layers found within the meristem of a hosta. (The three apical layers of cells within the meristem, or center, of a hosta can be genetically different. These layers are commonly designated as L1, L2, and L3.)
Like most plants, hostas generally are diploid, which means they have two sets of chromosomes. On the other hand, a plant may contain four sets of chromosome in each apical layer and therefore be a tetraploid (4-4-4). In a ploidy chimera, the three apical layers have different ploidy. An example of a ploidy chimera is 'Grand Tiara' (4-2-2) which has four sets of chromosomes in layer 1 and two sets of chromosomes in layers 2 and 3.
Occassionally, a plant may have an abnormal number of chromosomes in one or more of the apical layers. This is a case in which there are extra or missing chromosomes and is known as aneuploidy. An example of an aneuploid hosta is 'Mango Tango' (4-A-4) which has an abnormal number of chromosomes in the center apical layer of the meristem.
Most of the work of flow cytometry testing with hostas has been conducted by Ben J. M. Zonneveld and Frank van Iren at Leiden University in The Netherlands and is presented in the list that follows.
Also see the "Polyploid Hostas" list.
Sources: Flow cytometric analysis of DNA content in Hosta reveals ploidy chimeras (Ben J. M. Zonneveld and Frank Van Iren, Institute of Molecular Plant Sciences, Leiden University, 2000); Nuclear DNA content of ploidy chimeras of Hosta Tratt. (Hostacae) demonstrate three apical layers in all organs, but not in the adventitious root (B. J. M. Zonneveld, Institute of Biology, Leiden University, 2007); Zonneveld's Study of Cell Layers and Leaf Variegation in Hosta Cultivars: A Summary (Steven C. Chamberlain, The Hosta Journal, 2008, Volume 39, Number 2); H. 'Stitch in Time': A Multiple Mystery (Ben J. M. Zonneveld, Warren I. Pollock, Rob Mortko, and Steven C. Chamberlain, The Hosta Journal, 2009, Volume 40, Number 1), Ploidy and Pollen Viability in Hosta Cultivars: Zonneveld's Data Sets (Steven C. Chamberlain, Warren Pollock, and Ben J. M. Zonneveld, The Hosta Journal, 2011, Volume 42, Number 1. Do You Know a Tetraploid Hosta When You See One? (Bob Solberg, The Hosta Journal, 2011, Volume 42, Number 2); What's in a Hosta Name? Part LIII (Warren I. Pollock, The Hosta Journal, 2011, Volume 42, Number 2); This and That: 2011 (Warren I. Pollock, The Online Hosta Journal, Volume 42 Online); regarding analysis of hosta 'Doubled Up' by Zonneveld, source of information is Greenhill Farms website, www.hostahosta.com; regarding analysis of hosta 'Neutron Star' by Zonneveld, source of information is the registration sheet at www.hostaregistrar.org.
1 According to Flow cytometric analysis of DNA content in Hosta reveals ploidy chimeras by Zonneveld, H. 'Little Blue' is incorrectly identified as a tetraploid (page 3) and an aneuploid (page 5). Zonneveld has since determined H. 'Little Blue' to be a triploid.
2 According to Table 2. Tetraploid Hostas from Tetraploid Parents (ibid., page 76), H. 'On Stage' is incorrectly presented as a tetraploid. In his article Flow cytometric analysis of DNA content in Hosta reveals ploidy chimeras, Zonneveld confirmed that H. 'On Stage' is a diploid.
3 According to This and That: 2011 (Warren I. Pollock, The Online Hosta Journal, Volume 42 Online), H.'Bubba' is aneuploid, not diploid as previously published in Ploidy and Pollen Viability in Hosta Cultivars: Zonneveld's Data Sets (Steven C. Chamberlain, Warren Pollock, and Ben J. M. Zonneveld, The Hosta Journal, 2011, Volume 42, Number 1.
In an effort to keep this list accurate and up-to-date, please email all corrections and additions to