ABSTRACT Five species of Trillium ...

ABSTRACT

Five species of Trillium are recognized as occurring in Texas. individual species, Trillium pusillum var. texanum has the major part of its distribution in the state, while another species, T gracile, is endemic to Louisiana and Texas. Three species, T ludovicianum, which is reported as of the present day to the state, T. recurvatum, and T viridescens are considered to be peripheral species. The thought based upon field work and cogitation of herbarium specimens, includes a solution to species, partial synonymy, descriptions, specimen citations, and a distribution map of the species.

INTRODUCTION

Trillium (Liliaceae) is a woodland genus of about 45 species distributed in temperate North America and temperate east Asia (Freeman 1975) Freeman attributes eight species to Asia, seven species to western North America, and about 35 species to eastern North America. The genus is about equally divided into pair subgenera, those with pedicellate flowers (Trillium L) and those with sessile flowers (Phyllantherum Raf.). Texas has four species of sessile flowered Trillium, three of which may be considered "peripheral species;" i.e., the major portion of their distribution occurring outside of Texas. united species, T. gracile, is endemic to east Texas and adjacent Louisiana. The simply pedicellate flowered species in the state, T pusillum var. texanum, is part of the T pusillum tangle which occurs in a series of widely disjunct populations from end to end much of the southeastern United States (Case and Case 1997) This variety is largely confined to Texas, still is known from extreme northwest Louisiana. The genus is generally limited to the East Texas Forest Region (the "pineywoods" of Gould 1962) which Correll and Johnston (1970) consider to be part of the vast southeastern United States pine-hardwood forest. Trillium gracile is also known to take place in the Post Oak Savannah and the opening Prairies and Marshes vegetation areas (as delineated on Gould 1962), both conterminous with the pinewoods, while T viridescens also flash on the minds in the Post Oak Savannah. However, as well-as; not only-but also; not only-but; not alone-but species attain their greatest abundance in the pineywoods.

As a assign places to members of the genus Trillium are commonly known as trillium, wakerobin, toadshade, squawroot, or carrion flower and they have lately gained interest as garden plants. Trillium pusillum var. texanum was a former candidate for listing as state threatened if it be not that has not gained protective status because of its abundance. Trillium recurvatum and T viridescens attain the southwestern limits of their overall distribution in the state while T ludovicianum reaches the western compass of its distribution in southeast Texas. The uncommones of the latter three species in the state is reason enough to warrant monitoring their known populations and, at the same time, searching for additional incidents

With common exception, knowledge of Trillium in the state has been the conclusion of botanical studies conducted since 1962 For example, Gates (1917) in his systematic treatment of the genus in North America, does not attribute any species to Texas. overtoped was Buckley's (1861) proposal of the binomial T texanum, now considered a variety of T pusillum (Reveal and Broome 1981 Freeman 1994) In a checklist of the vascular flora of the state, Gould (1962) also missing the Buckley proposal, listed solitary T. ludovicianum for the state. Nixon et al. (1970) however, considered Gould's report to be based forward a misdetermination of T. gracile, a species not propos until 1969 as T ludovicianum. Trillium viridescens was initially reported in Texas by way of Freeman (1969a), but it did not become generally known as occurring in the state until the publication of his 1970 treatment of the genus, which appeared after the Nixon et al. (1970) manuscript reporting T recurvatum as of recent origin to the state. To date, the greatest in number comprehensive treatment of the genus for the state was by dint of Freeman (1970) in which four species are included. Freeman (1975) included three species that befall in Texas in his important work onward the sessile-flowered Trillium. More lately the four species known from Texas are treated in Case and Case (1997) yet T. ludovicianum was not known to arise in the state at that time.

This particular treatment considers all species of the genus known to be found naturally within the state. Descriptions, flowering dates, and the solution are based upon Texas materials. The taxonomy generally go afters the concepts of Freeman (1975 1994) and to a less extent, that of Case and Case (1997) Specifically the treatment is based about field studies conducted in east Texas, with a limited amount of cogitation in nearby states, and examination of herbarium specimens from the following herbaria of the state: ASTC, BAYLU, BRIT, LL SMU TAMU, TAES, and TEX The lists of specimens examined are limited to the same record per county (usually the oldest numbered collection) exclude for Trillium ludovicianum in which case all studied specimens are cited.

The intent of this paper on Trillium is to report a species of the genus strange to Texas, provide a means for identification, update the known distribution of each of the species on county, and provide other information of interest.