Thomas F. Patterson

Picea martinezii, the Martinez's spruce, or Nuevo León spruce, is a medium-sized evergreen tree growing to 25–35 m tall, and with a trunk diameter of up to 1 m. It is native to northeast Mexico, where it occurs at six localities in the Sierra Madre Oriental mountains in Nuevo León. It grows at moderate altitudes from 2150–2600 m, growing along streamsides in mountain valleys, where moisture levels in the soil are greater than the otherwise low rainfall in the area would suggest. The bark is thin and scaly, flaking off in small circular plates 5–10 cm across. The crown is conic, with widely

Conoclinium mayfieldii is a Mexican species of flowering plants in the family Asteraceae. It has a discontinuous distribution, found in the Sierra Madre Occidental in Chihuahua and Durango, and also in the Sierra Madre Oriental in Tamaulipas. These two mountain ranges are separated by the Chihuahuan Desert, 400 km wide. Conoclinium mayfieldii is a reclining herb up to 70 cm (28 inches) tall. Leaves are opposite, egg-shaped. The plant usually produces several flower heads, each with blue or lavender disc florets but no ray florets. The species is named for American botanist Mark H. Mayfield.

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