Stevia perfoliata Cronquist
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Authority
Cronquist, Arthur J. 1965. Studies in Mexican Compositae. I. Miscellaneous new species. Mem. New York Bot. Gard. 12: 286-292.
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Family
Asteraceae
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Scientific Name
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Type
Type. Cronquist 9715, steep, east-facing, calcareous slopes in open, grassy oak-pine woods; Sierra Madre del Sur, about 10 road miles west of Chilpancingo, state of Guerrero, Mexico. Elevation about 5400 feet. October 21, 1962. Holotype at NY.
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Description
Latin Diagnosis - Herba perennis ca. 1 m alta omnino glanduloso-pubescens, foliis serratis oblongo-ovatis usque ad 7 cm longis 4.5 cm latis perspicue connato-perfoliatis; capitula plurima conferta sessilia vel breviter pedunculata, involucro 8-9 mm alto bracteis anguste cacuminatis; floribus purpureis corolla fere 1 cm longa, achaeniis 5 mm longis pappo quattuor ex aristis longis tribus et squamellis brevibus tribus, quintius squamellis solis composito.
Species Description - Fibrous-rooted perennial about 1 m tall, the solitary stem evidently spreadinghairy throughout, many of the hairs, especially the shorter ones, gland-tipped; leaves firm, glandular-hairy like the stem, but the pubescence somewhat shorter and, on the lower surface, sparser; lowermost leaves reduced and deciduous, the others well developed, about a dozen pairs below the inflorescence, up to 7 cm long and 4.5 cm wide, sharply serrate, ovate-oblong, scarcely narrowed at the base, sessile and evidently connate-perfoliate; heads crowded in a round-topped inflorescence about 1 d m wide, sessile or on short peduncles up to 5 mm long; involucre 8-9 mm high, shortly glandular-hirsute or stipitate-glandular, the bracts firm, strongly carinate below, tapering above to a narrow, almost subulate point; corolla purple, 8-9 mm long (dry) ; achenes black, 5 mm long, hirtellous-scabrous; pappus of 4 achenes in each head composed of 3 long awns about equaling the corolla and 3 alternating short, broad, hyaline scales only 0.5 mm long, of the fifth achene awnless, composed of short scales only.
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Discussion
This species diff'ers from all other Stevias known to me, and certainly from all other North American species, in its evidently connate-perf oliate leaves. Both the general aspect and the technical characters are clearly of Stevia, but it does not seem particularly closely related to any other species. Only a few plants were seen, and of these only one was suitable to become a good herbarium specimen. The species is therefore represented in the herbarium only by its holotype.