Two Lesquerellas (Cruciferae) of South Central and Western Montana Reed C. RollinsGray Herbarium of Harvard University, 22 Divinity Avenue, Cambridge, Massachusetts 02138, U.S.A.ABSTRACT. Two heretofore unknown species ofLesquerella are described. These occur in limitedareas in the mountains of central and western Mon-tana. Both species, here named L. lesicii and L.pulchella, occur in patches of limestone-derivedsoils and rubble that are conspicuously barren oftrees and shrubs and other types of plant cover, oron the borders of such areas where the limestonedetritus meets soils and rubble of crystalline rocks.Also, they are often found in open areas in sparsestands of low-growing trees or shrubs. Recent samplings of populations of Lesquerellain Montana show that species diversity in this genusgoes somewhat beyond that previously recognizedin monographic treatments (Payson, 1922; Rollins& Shaw, 1973; Rollins, 1993). What has beenknown for the area is that species of Lesquerellaare often abundant and are an important componentof the flora of specialized habitats, especially wherelimestone or derivatives of limestone are involved.The nature of some of these habitats is well shownin Figures 1 and 2, where the highly reflectivelimestone-derived soil and rubble contrast with themore vegetated surrounding areas. These windsweptwhitish areas are the places where L. pulchellagrows. Also known is that a high degree of com-plexity exists within some species, such as L. alpina(Nuttall ex Torrey & A. Gray) S. Watson, which isfrequently encountered in the general region. Butnow we see that there are existing taxa not previ-ously recognized, and these have complicated re-lationships with species south of Montana in Idahoand Wyoming. The main purpose of this paper isto describe two new species of Lesquerella and ex-plain their relationships to previously known taxa.It is somewhat ironic that I had only recently (Rol-lins, 1993) completed a review of Lesquerella as itoccurs in North America when these two speciesshowed up too late to be included in my treatment.Lesquerella lesicii Rollins, sp. nov. TYPE: U.S.A. Montana: abundant in gravelly limestone-de-rived soil at edge of limber pine woodland on the ridge W of Layout Creek, 4/ mi. S of Mys-tery Cave, Pryor Mountains, Carbon County, 7500 ft., T85, R28 E, S21, SW /,, with Shosh-onea pulvinata, Astragalus aretoides, and A. miser, 20 June 1992, Peter Lesica 5707 and Rob DeVelica (holotype, GH). Herba perennis, caudicibus simplicibus, folia basibuserectis dense stellatis argenteis 0.5-1 cm longis, cauliserectis vel decumbentibus gracilibus 1-1.5 dm longis,petalis aureis spathulatis vel lingulatis 6-7 mm longis,pedicellis fructiferis recurvatis vel divaricatis 5-10 mmlongis, siliquis globosis vel subglobosis 3-4 mm diametropilis stellatis adspersus, loculis 3-5 ovulatis. Delicate perennial; caudex simple, sometimeselongated and with old leaf bases; basal leaves erect,usually fewer than 10, entire, 1.5-3 cm long, pet-ioles slender, abruptly expanded to blade, 1-2.5 cmlong, blades broadly ovate to elliptical, 0.5-1 cmlong, silvery from a dense cover of stellate trichomes;leaf trichomes small, ca. 0.02 mm diam., ray tips15-25, each primary ray forked near its base; flow-ering stems very slender, mostly filiform, simple,erect to decumbent, 1-1.5 dm long; cauline leavesfew, remote, � spatulate, lower somewhat petiolate,upper cuneate at base; inflorescences lax, rarelynodding, usually with fewer than 10 flowers; sepalserect, densely pubescent, oblong, nonsaccate andwithout scarious margins, 3.5-4 mm long; petalsyellow, often fading to light purple toward their tips,spatulate to nearly lingulate, 6-7 mm long; stamensstrongly tetradynymous; infructescences lax, greatlyelongated; fruiting pedicels filiform, recurved in asingle arch to widely spreading, 5-10 mm long;siliques globose or subglobose, spreading at rightangles to rachis to pendent, 3-4 mm diam., �densely pubescent on exterior, valves glabrous onthe interior; styles ca. 1.5 mm long, glabrous or NovoN 5: 71-75. 1995.
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