GENUS 76. 



THISTLE FAMILY. 



503 



Leaves ovate, oval, or ovate-lanceolate, 3-nerved. 



Leaves linear, lanceolate, or the basal spatulate, or obovate. 



Chaff of the receptacle linear ; leaves linear ; western. 



Chaff of the receptacle broader ; leaves obovate to lanceolate ; eastern. 



i. Marshallia trinervia (Walt.) Porter. Broad- 

 leaved Marshallia. Fig. 4524. 



Athanasia trinervia Walt. Fl. Car. 201. 1788. 

 Marshallia Schreberi Gmelin, Syst. 1208. 1791. 

 Marshallia latifolia Pursh, Fl. Am. Sept. 519. 1814. 

 Marshallia trinervia Porter, Mem. Torr. Club 5: 337. 1894. 



Stem simple, or little branched, leafy to or beyond the 

 middle, i-2 high. Leaves thin, those cf the stem 

 ovate, oval or ovate-lanceolate, 3-nerved, acute or acumi- 

 nate at the apex, narrowed to a sessile base, 2 '-3' long, 

 g"-i8" wide; heads i'-i' broad, corolla purplish; bracts 

 of the involucre linear-lanceolate, acute, rigid; chaff of 

 the receptacle subulate-filiform; pappus r:alc-3 lanceo- 

 late-acuminate from a triangular base; achenes gla- 

 brous when mature. 



In dry soil, Virginia to Alabama and Mississippi. May- 

 June. 



1. M. trinervia. 



2. M. caespi osa. 



3. M . grandiflora. 



2. Marshallia caespitosa Nutt. Narrow-leaved 

 Marshallia. Fig. 4525. 



Marshallia caespitosa Nutt.; DC. Prodr. 5: 680. 1836. 



Stems usually tufted and simple, sometimes sparingly 

 branched, leafy either only near the base or to beyond 

 the middle, 8'-i5' high. Leaves thick, mostly basal, 

 faintly 3-nerved, linear or linear-spatulate, obtuse, some- 

 times 4' long and 3" wide, the upper ones linear, acutish, 

 shorter; head about i' broad, borne on a peduncle often 

 10' long ; corollas pale rose or white ; bracts of the. invo- 

 lucre linear-lanceolate, acute or acutish; chaff of the 

 receptacle linear, or slightly dilated above ; achenes vil- 

 lous on the angles ; scales of the pappus ovate, acutish, 

 equalling or longer than the achene. 



Prairies and hills, Missouri and Kansas to Texas. May- 

 June. 



3. Marshallia grandiflora Beadle & 



Boynton. Large-flowered Marshallia. 



Fig. 4526. 



Marshallia grandiflora Beadle & Boynton, Bilt- 

 more Bot. Stud, i: 7. 1901. 



Stem simple, i-2 high, leafy to above the 

 middle. Lower and basal leaves obovate to 

 oblong-lanceolate, tapering into petioles often 

 as long as the blade, obtuse or obtusish ; 

 upper leaves lanceolate, sessile, or more or 

 less clasping ; florets slightly larger than those 

 of M. trinervia, 7"-io" long; achenes larger, 

 2"-2i" long, pubescent. 



In moist soil, Pennsylvania to West Virginia 

 and North Carolina. July-Aug. 



Marshallia obovata (Walt.) Beadle & Boyn- 

 ton, a lower plant of the Southern States, with 

 obovate or spatulate leaves mainly basal, is re- 

 corded as extending northward to southwestern 

 Pennsylvania. 



