Miscanthus sinensis plant named ‘NCMS2B’

Latin name of the genus and species: The Latin name of the novel plant variety disclosed herein is Miscanthus sinensis.

Varietal denomination: The inventive variety of Miscanthus sinensis disclosed herein has been given the varietal denomination ‘NCMS2B’.

The present invention comprises a new and distinct cultivar of miscanthus , botanically known as Miscanthus sinensis , and hereinafter referred to by the cultivar name ‘NCMS2B’. This new miscanthus was developed and selected in Mills River, N.C. ‘NCMS2B’ is a triploid produced from a controlled pollination. The female parent was an artificially induced tetraploid derived from seed from an open pollinated Miscanthus sinensis ‘Little Zebra’ (U.S. Plant Pat. No. 13,008). The male parent was a diploid seedling from an open-pollinated Miscanthus sinensis ‘Little Zebra’.

‘NCMS2B’ was first established in vitro in 2010 through embryo rescue techniques and has been asexually reproduced through micropropagation and division in Mills River, N.C. over a 4-year period. ‘NCMS2B’ has been evaluated in the field and containers for 4 years. ‘NCMS2B’ can be propagated through micropropagation or division and has been found to retain its distinctive characteristics through successive asexual propagations.

The following traits have been repeatedly observed and are distinguishing characteristics of this new cultivar when grown under normal horticultural practices in Mills River, N.C.

1. ‘NCMS2B’ is a triploid Miscanthus sinensis with a 2C genome size of approximately 5.9 picograms (pg). 2. ‘NCMS2B’ is highly infertile with no seed produced in control crosses with Miscanthus sinenesis ‘Zebrinus’ and Miscanthus sinenesis ‘Super Stripe’. 3. ‘NCMS2B’ has upright culms and cascading, variegated leaf blades resulting in an attractive compact form.

‘NCMS2B’ is illustrated by the accompanying photographs, which show the plant's form and foliage. The colors shown are as true as can be reasonably obtained by conventional photographic procedures.

FIG. 1 shows a one-year-old container grown plant in Mills River, N.C. in January, 2017.

FIG. 2 shows leaves and banding patterns from a one-year-old container grown plant in Mills River, N.C. in January, 2017.

The following detailed description sets forth the distinctive characteristics of ‘NCMS2B’. The detailed description was taken on 1-year-old container-grown plants in Mills River, N.C. in August-January 2016-2017. Color references are to The R.H.S. Colour Chart of The Royal Horticultural Society of London (R.H.S.), 2015 Edition. Where specific dimensions, sizes, colors, and other characteristics are given, it is to be understood that such characteristics are approximations or averages set forth as accurately as practicable.

Botanical classification:

Botanical name.—Miscanthus sinensis. Common name .—Maiden grass. Variety name .—‘NCMS2B’. Parentage .—Female parent: Induced tetraploid (accession, H2010-268-001; 2C genome size of approximately 8 pg) derived from open pollinated seed from Miscanthus sinensis ‘Little Zebra’. Male parent: Diploid seedling (accession H2010-269-001; 2C genome size of approximately 4.1 pg) from and open-pollenated Miscanthus sinensis ‘Little Zebra’.

General description:

Blooming period .—Late August through early September in Mills River, N.C. Plant habit .—Clump forming ornamental grass, rigid upright culms and cascading variegated leaf blades. Height and spread .—Reaches a height, including inflorescences, of 0.9-1.2 M (foliage approximately 0.6-0.9 M high), spread at base approximately 0.3 M, foliage cascading to approximately 0.6 M in diameter in 3 years. Cold hardiness .—At least USDA zone 6; testing has not been completed in colder zones. Culture .—Optimal growth in fertile moist soil in full sun. Disease and pests .—No significant disease or insect pests have been observed. Root description .—Fibrous. Propagation .—Propagated through culm division and micropropagation.

Culm (stem) description:

General .—Cylindrical, smooth, partially enclosed by leaf sheaths. Culm aspect .—Erect and rigid, all extending from ground, non-cascading. Culm color.— 138A. Culm size .—Up to 3 to 5 mm wide, 0.6-0.9 M high in mature plants. Culm surface .—Glabrous. Internode length.— 2 to 6 cm. Ligule .—Membranous, about 2-3 mm in width.

Foliage description:

Leaf shape .—Linear. Leaf division .—Simple. Leaf base .—Sheathed. Leaf apex .—Acute. Leaf aspect .—Emerging leaves are erect and diverge from the sheath at an angle in the range of 30° to 45° from the center of the culm. Leaves are concave with respect to the culm. Leaf venation .—Parallel, mid rib is recessed on upper surface and extends through entire leaf and is white (NN155D). Leaf margins .—Entire, crenulate with small membranous serrations. Leaf persistence .—Leaves desiccate after freezing, but remain attached to the culm through winter. Leaf attachment .—Sheathed. Leaf blade extends out from the culm at a ligule. Leaf size .—Up to 30 cm in length and 5-8 mm in width, tapering to a point at the apex. Leaf surface .—Glabrous on the adaxial (upper) and abaxial (lower) surface with ribbing protruding on the abaxial surface parallel to the mid rib. Leaf number .—About 8 to 12 per culm on a mature plant. Leaf arrangement .—Alternate, 2 ranked. Leaf color .—Variegated with green 135A on the adaxial (upper) surface and 139A on the abaxial (lower) alternating with bands of yellow 6D (both sides). Green bands range from 0.25 to 14 cm longitudinally and yellow bands range from 0.25 to 1 cm longitudinally.

Flower description: General description:

Lasting of the infloresence .—Panicles are persistent throughout winter. Fragrance .—None. Panicle size .—Not available at present time. Panicle color .—Not available at present time. Raceme ( spike ) description .—Not available at present time. Spikelet description .—Not available at present time. Spikelet size .—Not available at present time. Spikelet hairs .—Not available at present time.

Reproductive organs:

Androceum .—Not available at present time. Gynoecium .—Not available at present time.

Fertility: In controlled crosses under greenhouse conditions with Miscanthus sinensis ‘Zebrinus’ and Miscanthus sinensis ‘Superstripe’ as male parents, ‘NCMS2B’ showed no seed production (Table 1).

Where seed set (%)=(number of seeds/number of florets)×100; germination (%)=(seeds germinated/total seeds)×100; overall fertility=seed set (%)×germination (%)/100; and relative fertility=[overall fertility/55.3 (control value)]×100. As such, ‘NSMS2B’ provides an attractive and highly infertile alternative to diploid cultivars where reseeding and naturalization is a concern (see Rounsaville et al., 2011).

‘NCMS2B’ is distinguished from its parents by its intermediate triploid cytotype. ‘NCMS2B’ is distinguished from other variegated Miscanthus cultivars, including ‘Little Zebra’, ‘Strictus’, and ‘Zebrinus’ by its triploid cytotype, smaller stature and lower fertility when compared to ‘Zebrinus’. ‘NCMS2B’ is distinguished from ‘NCMS1’ in that ‘HCMS2B’ is variegated and smaller in stature. See, Table 2, below.

Rounsaville, T. J., D. H. Touchell, and T. G. Ranney. 2011. Fertility and reproductive pathways in diploid and triploid Miscanthus sinensis. Hortscience 46(10):1353-1357.