Monographs Details: Senecio marquezii B.L.Turner
Authority: Turner, B. 1988. Two New Species of Senecio Section Palmatinervii (Asteraceae) from Eastern Mexico, 40: 81-84.
Description:Species Description - Perennial herb to 2 m high. Stems terete, densely hirsute with multiseptate, crinkled hairs. Leaves palmately veined, 7-13-lobate, the margins minutely denticulate to nearly entire, the petioles 5-10 cm long, hirsute, blades rounded in outline, ca 15 cm long, 15 cm wide, moderately hirsute on both surfaces. Capitulescence a terminal bracteate panicle with 20-40 campanulate heads. Involucre of ca 11 linear lanceolate bracts 10-12 mm long, ca 1.5 mm wide, short glandular pubescent dorsally, moderately interspersed with much longer, multiseptate tri-chomes, the apices with a tuft of short hairs; calyculum (or enlarged bracts just below the involucre) comprised of 5-8 ovate to obovate, ciliate bracts mostly 1 0- 15 mm long, 3-5 mm wide, the head thus appearing to have a markedly biseriate involucre. Ray florets 13-21, pistillate, fertile; corolla yellow, the tube 5-7 mm long, glabrous, the ligules 10-15 mm long, 3-5 mm wide, 4-6-nervate. Disk florets 30-60; corollas yellow, glabrous, 8-9 mm long; the tubes 4-5 mm long, the limb narrowly funnelform, ca 4 mm long, the lobes ca 1 mm long. Anthers ca 3.5 mm long, the appendages narrowly ovate, ca 0.5 mm long. Achenes ca 3 mm long, decidedly pubescent; pappus of 50-80 white, fragile bristles 8-10 mm long
S. grimesii affinis, sed imprimis flosculis radiatis et achaenii pubescentibus
TYPE: MEXICO. VERACRUZ: Salto del Gato, 4 km al este de Xalapa (19º35'N, 96º53'W), ca 1500 m, "Bosque caducifolio, secundaria, suelo rojizo profundo," 4 Apr 1972, W. Marquez R. 24 (HOLOTYPE: TEX; isoTYPEs: KSC, MEXU, XAL).
Additional specimen examined: MEXICO. PUEBLA: Mun. Zaragosa, Cerro Totoltepec, 10 km N of Zaragoza on the road to Zacapoxtla, ca 1920 m, 12 Apr 1985, Tenorio, Grimes & Martinez 8639 (TEX)
Senecio marquezii was first collected on the western outskirts of Xalapa at Salto del Gato, a deep canyon which is known to house several localized endemics (e.g., Eupatorium xalapanum B. Turner; Turner, 1985). The Puebla collection is note- worthy for its much larger ligules and much more pubescent achenes, otherwise it is very similar to the Xalapa collections. The species is named for W. Marquez R., an active field collector working out of INIREB (XAL).
Senecio marquezii is very similar vegetatively to S. grimesii, described above, but the latter is eradiate with more numerous disk florets and possesses glabrous achenes (or seemingly so). These two species are certainly more closely related to each other than either is to yet other species, but both appear to be closest to S. heterogamus. Future work among the east-facing canyons along the Sierra Madre Oriental may show that intergradation between the two newly described taxa occurs, but lacking such populational information specific recognition would seem appropriate.