Mexico 2013 Flora de San Luis Potosi y Queretaro

Voucher:AN 472

Tetrachyron omissum Rzed. & Calderón

Location:San Luis Potosi, Xilitla, La Trinidad, on top of 'El Pilon'
Coordinates: 21°23'55" N, 99°04'34" W Alt: 2144m

Small shrub 40 cm tall. Flowers yellow. Leaves glossy.
Rock outcop above the forest. Growing on SW side of the rocks with Vesalea and Cyperaceae.

Identification Notes: Verified with Jerzy Rzedowski 2008 'Flora del bajío y de regiones adyacentes Compositae tribu Heliantheae' Vol 157. Tribe Heliantheae. Shrubby plant with opposite leaves. Leaves coriaceous, glabrous and with a crenate margin. Inflorescence paniculate, capitula radiate. Ray florets yellow, fertile. Disc florets yellow and bisexual. Phyllaries in several whorls, lanceolate becoming cartilaginous in fruit. Receptacle very conical, with ovate and ciliate palea. Cypsela flattened or three angular sligthly winged. Pappus of 4-5 equal lanceolate scales longer than ovary. Species endemic to this area, first record for San Luis Potosi.

Nova, J.A. de #472      14 June 2013

morphological details

inflorescence inflorescence inflorescence rachis inflorescence rachis capitulum capitulum

phyllaries phyllaries

receptacle receptacle

ovary ovary

ovary ovary receptacular scale, disc and ray florets receptacular scale, disc and ray florets receptacular scale, disc floret receptacular scale, disc floret
disc floret disc floret androecium section androecium section ovary, pappus ovary, pappus
fruiting capitulum fruiting capitulum capitulum section capitulum section cypsela cypsela
stem stem abaxial leaf surface abaxial leaf surface abaxial leaf surface abaxial leaf surface
field picture
Herbarium voucher
Herbarium voucher

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