ABSTRACT Ten species of Trillium (L...

ABSTRACT

Ten species of Trillium (Liliaceae) are known to appear in Virginia. Taxonomic key, morphological descriptions, distribution maps and chromosome numbers are at handed A chromosome number of 2n = 10 was verified for: Trillium cernuum T erectum T flexipes, T grandiflorum, T luteum T nivale, T pusillum, T sessile, T sulcatum, and T undulatum. one chromosome morphology data are applied to the discussion of T pusillum, and also reinforce that T sulcatum and T erectum are separate taxa.

INTRODUCTION

The genus Trillium is exhibited in three areas of the world: eastern Asia (8 spp); western North America (7 spp); and ca. 35 spp in eastern North America (Freeman 1975) The genus probably reaches its broadest unravelling in the Southern Appalachians (Barksdale 1938) Case (1981) states that at far the greatest number of species come about in the mountains, upper piedmont, and foothills of the southeastern United States from the Carolinas to Alabama and forward the Cumberland Plateau and surrounding areas of Kentucky and Tennessee It is also within the area of the Southern Appalachians that Trillium earns its reputation as a taxonomically difficult genus. Variation is universal between and within some populations (Duncan and Calhoun 1962 Serota 1969) Hybridization is a factor causing a of the variation, as is the case for the T erectum collection (Case 2002).

The purpose of this paper is to not absent a treatment of the genus Trillium as it is known in Virginia. Chromosome numbers are also existinged for the ten species.

Various taxonomic treatments of the genus from one side of to the other larger geographical areas have propos brace subgenera based on the appearance or absence of a pedicel. fundamental note characters in the genus are ovary lobation, features of the stigma, anther/filament ratio, leaf (or bract) shape, and whether or not the leaves are sessile or petiolate (Barksdale 1938 Freeman 1975 Gleason 1906 Gates 1917 and Case and Case 1997)

In Virginia there are reported chromosome computes of 2n = 10 for T grandiflorum (Fukuda and Grant 1980) T nivale and T pusillum (Hill 1995a) and for T cernuum (Hill 1995b) Chromosome morphological studies of Virginian trilliums are published for T grandiflorum (Fukuda and Grant 1980) and T pusillum (Baldwin 1949)

MATERIALS AND METHODS

The genus was studied from (1) herbarium specimens borrowed from waterfall WILLI, VPI, TENN, WVA, GH NA, GMUF and NCU (2) field work in Virginia, and (3) observations from the greenhouse. Floristic studies in Virginia were also deliberateed (Thorne and Cooperrider 1960, Carr 1965 Jervis 1969 Grimshaw and Bradley 1973 Hathaway and Ramsey 1973 and Ramsey et al. 1993)

For the chromosome work, a Fuelgen technique modified from Sharma and Sharma (1965) was raiseed using a pretreatment of colchicine. The slide was made permanent using a previously described technique (Hill and Roger 1970) Drawings were taken using a Zeiss phase contrast microscope beneath oil at 1,000?— using a drawing tube and a standard micrometer for measurements. These drawings are appended to the herbarium voucher specimens that are deposited at BDWR

TAXONOMIC TREATMENT

TRILLIUM LINNAEUS, Sp Pl 1:339 1753; Gen Pl ed 5, 158. 1754

Perennial scapose herbs with simple progenys from short, stocky, horizontal rhizomes bearing a whorl of 3 net-veined, blooming or mottled, ovate-obovate or elliptical bracts (leaves), petiolate or sessile, flower solitary. Flowers excellent sessile or pedicellate; sepals 3 alternating with the leaves, virid reddish or purplish; petals 3 (rarely 4-8) white, r maroon, purple pink, fulvous or green, ovate or obovate to linear; stamens 6 anthers linear forward short filaments; ovary superior, 3-6 lobed or winged, r white or pink, stigmas 3 sessile or fashion very short. Fruit a berrylike capsule, many kerneled globose or ovoid.

1. Trillium pusillum Michaux., Fl Bor.-Amer. 1:215 1803 Dwarf trillium, early trillium. T pusillum Michx. var. virglnianum Fernald. Rhodora 45: 397 plate 773 Figures 12 1943 T pusillum Michx. var. monticulum Bodkin & Reveal. Brittonia 34: 142 Figure 1 1982

Rhizomes white, horizontal to raise up to 10 mm thick, 3-6 cm lengthy Scapes 1-2, 1-2 dm high; glabrous. Bracts sessile or nearly in such a manner horizontal to drooping distally, 3-5 veined, not mottl 3-85 cm prolonged 1-2.5 cm wide, lance-elliptic or lance-ovate, obtuse. Flower above bracts, pedicel 05-25 cm in extent ascending. Petals white, aging to pink, and then to a pale purple 15-35 cm protracted 4-10 mm wide, undulate, nearly equal to or slightly longer than the sepals, linear-elliptic to linear. Stamens 5-10 mm protracted filaments broadened at the base, about as protracted as the yellow anthers. Ovary white, obtusely 3- angled with white stigmas spreading-ascending. Fruit about 1 cm extended ovoid or ellipsoid, greenish white. (2N = 10) Late March-late April. In the Coastal Plain, the habitat is remarkably often an open or shaded swamp. In western Virginia the habitats vary from compressed mixed deciduous forest of Quercus, Hamamelis and Rhododendron sp (Elliot Knob-Augusta County) to a more explain forest at Flagpole Knob (Rockingham County) of Pinus rigida Miller, Pieris floribunda (Sims) B & H Quercus rubra L and Kalmia latifolia L with the trillium scattered subordinate to the shade of these plants in haircap mos (Polytrichum). Figure 1a.