Brittonia, 43(2), 1991, pp. 120-122. �9 1991, by the New York Botanical Garden, Bronx, NY 10458-5126

P L A N T A E A L P I N A E NOV A E M E X I C A N A E : A R G E M O N E S U B A L P I N A (P A P A V ERA CEA E)

ANDREW MCDONALD

McDonald, Andrew (Department of Botany, University of Texas, Austin, TX 78713-7640). Plantae alpinae novae Mexicanae: Argemone subalpina (Papaver- aceae). Brittonia 43:120-122.1991.--A new species ofArgemone (Papaveraceae), A. subalpina, is recognized from the subalpine glades of Sierra Pefia Nevada, Nuevo Le6n, Mrxico. It is the first member of the poppy family to be associated with timberline vegetation in the New World. The new taxon is closely related to A. ptatyceras of the Mexican transvolcanic belt, but differs by retrorse cauline spines, broadly ellipsoid flower buds to 20 mm long, caudate sepal norns 3-5 mm long, and recurved fruit spines. Key words: Papaveraceae, Argemone, Mexico.

Argemone subalpina McDonald, sp. nov. (Fig. 1).

TYPE: MEXICO. Nuevo Le6n: Municipio Zaragoza, N end o f Sierra Pefia Ne- vada, N facing slopes near ridge-top, in meadows, 3000-3100 m, 25 Aug 1989, Nesom et al. 7140 (HOLOTYPE: TEX!; ISOTYPES: MEXU!, NY!, UAT!).

Sepalorum aculeis infirmis, fructibus ellipsoideis et dispersione montana habitat A. platyceras Link & Otto aemulans, sed spinis caulinis retrorsis sepalorum cornubus leretiusculis 4--6 mm longis et fructuum spinis recurvis 3-9 mm longis differt.

Robust , erect, perennial herbs 3-10 dm tall. Stems branching distally, glaucous, substriate, scantily spinose throughout , the majori ty o f the spines retrorse, 2 .5- 5.0 m m long. Leaves sessile; lamina lobed and incised, armed, glaucous, glabrous, the lower narrowly elliptic, 15-20 cm long, 3-5 cm wide, lobes 15-17, grading into the upper leaves, broadly elliptic to obovate, 3-5 cm long, 2-3 cm wide, lobes 5-7, terminating in stout prickles, the lower surface moderate ly prickly or with conspicuous papillae on the pr imary and secondary veins, the upper surface scantily prickly along the pr imary vein. Flowers solitary, often clustered loosely in terminal branchlets in groups o f 4; mature buds broadly ellipsoid and t runcated at the apex, 1.7-2.0 cm long, 1.3-1.5 cm wide; sepals broadly elliptic, 1.7-2.0 cm long, 2 -3 cm wide, glabrous and sparingly armed, the prickles weak, ca 2 m m long, patent, the sepal horn flattened, erect or recurred, 4-6 m m long, ca 1 m m wide at the base, glabrous, coriaceous, terminating at the tip in a small prickle 1- 2 m m long; corolla 8-9 cm across during anthesis, petals white, obcuneate, 5 .0- 5.5 cm long, 4.5-7.5 cm wide; s tamens ca 150; filaments 6-10 m m long, anthers 2-3 m m long; stigma 4-lobed, ovo id and undulate along margins, 3-4 m m wide; ovary ellipsoid, densely armed; capsules 4-carpellate, narrowly ellipsoid initially, broadly ellipsoid at maturity, 2 .4-3.4 cm long, 1.2-1.5 cm wide, valves reflexing at apex, closely armed, spines varying in size, to 9 m m long, obscuring surface until capsules are thoroughly dry, recurved at maturi ty; seeds 2.5-3.0 in diam, black, reticulate, glabrous.

Additional specimen examined: MEXICO: Nuevo Leon: Mpio. Zaragoza, Sierra Pefia Nevada, E side of sierra in subalpine vegetation, 3500-3600 m, 5 Jul 1985, McDonald 1612 (MEXU, TEX).

Almost all species of Argemone L. (Papaveraceae; ca 23 spp.) thrive best in disturbed, temperate habitats. Members o f the genus generally occur f rom 0-1300 m in elevation, with the except ion o f the closely related species, A. arida Rose and A. platyceras Link & Otto, which are occasionally encountered in open terrain

1991 ] McDONALD: ARGEMONE 121

A

C ~ ",' 5mm 5ram I

F]G. 1. Argemone subalpina (Nesom et aL 7140, TEX). A. Fertile branch. B. Adaxial view of sepal apex. C. Abaxial surface of sepal. D. Dry, dehisced capsule.

as high as 2300 m and 3300 m, respectively (Ownbey, 1958). Although a few Asian genera o f Papaveraceae (Papaver L. and Meconopsis Vig.) have radiated into alpine habitats, no New World poppy has yet been reported above timberline. A new and notewor thy species reported here, A. subalpina, occurs as a narrow endemic in the subalpine meadows and open glades o f high-montane, coniferous forest o f Sierra Pefia Nevada, Nuevo Le6n, f rom 3000-3600 m in elevation.

Argemone subalpina is morphologically intermediate between A. arida, a wide- spread species occurring on the eastern slopes o f the Sierra Madre Occidental, and A. platyceras, an endemic to the transvolcanic belt o f Mexico (Ownbey, 1958). Argemone subalpina shares with A. arida laminas with spines restricted to the pr imary and secondary veins, 120-150 stamens, and simple, relatively abundant , ascending fruit spines. Argemone arida is distinguished, however, by stems with

122 BRITTONIA [VOL. 43

perpendicular or moderately recurved spines, sepals with stout spines 3-5 mm long, subterminal sepal "horns" (sensu Ownbey, 1958) attenuate, 7-12 mm long, the upper half of which is fully sclerified into a stout, yellowish spine, corollas white or pale yellow, and fruits bearing scattered, erect, relatively homogeneous spines 8-10 mm long. Argemone subalpina differs by stems with retrorse spines, appressed sepal prickles to 2 mm long, a coriaceous, short-caudate sepal horn 4- 5 mm long, bearing at the tip a weak prickle, white corollas, and capsules densely covered with spines of varying lengths (3-9 ram) which obscure the surface during maturation, often becoming recurved at maturity (Fig. 1).

Argemone subalpina more closely approaches A. platyceras in habit, both species exhibiting a relatively more herbaceous and less spiny habit than A. arida, and sepals with weak prickles and flattened horns. Argemone platyceras differs from A. subalpina, however, on the basis of perpendicular cauline spines, ellipsoid flower buds 20-27 mm long, 1.4-1.8 cm wide, sepals bearing linear, herbaceous, flattened, subterminal horns 7-12 mm long, 2-3 mm wide at base, and straight fruit spines 7-8 mm long. Argemone subalpina has retrorse cauline spines, broadly ellipsoid flower buds 17-20 mm long, 1.3-1.5 cm wide, sepal horns 3-5 mm long, and fruit spines 3-9 mm long, the longer ones recurred. Only one other species of prickly poppy, A. brevicornuta Ownbey, exhibits sepal horns as small as those ofA. subalpina. The former species is probably only distantly related to A. sub- alpina, however, based on its densely distributed erect spines on stems and leaves, narrow (8-10 mm wide) and sparsely spinose fruits, and a narrow distribution in lower altitudes (1300-1700 m) of southern Chihuahua. While Ownbey (1958) considered A. arida and A. platyceras to be sister species, the recently discovered A. subalpina appears to enter into this alliance as well, forming a phylogenetic triad of closely related, high-altitudinal Argemone.

Literature Cited

Ownbey, G. B. 1958. Monograph of the genus Argemone for North America and the West Indies. Mem. Torrey Bot. Club 21: 1-159.

Historical Section, Botanical Society of America:

Since 1977, the Historical Section of the BSA has sponsored at the Annual AIBS Meeting a special lecture. This year we are privileged to have Stanley L. Welsh of Brigham Young University, Provo, Utah to speak on the Botanical Contributions of John Charles Fremont. Dr. Welsh's lecture is scheduled for Tuesday, August 6, 1991 at 11:00 AM. Please consult the AIBS General Program for the location of his talk.

For further information concerning the activities of the Historical Section, BSA please contact: Laurence J. Dorr, New York Botanical Garden, Bronx, NY 10458-5126.