Wednesday, May 17, 2006

A Prickly Pair

Monday’s walk at Red Rocks Park was full of flowers. With the late snows delaying the earlier species, and the later ones now beginning to bloom, it seemed like ‘everything’ was flowering at once! Or getting ready to. Shrubs, early and late wildflowers, and even a few cacti. I still haven’t caught up with the photos taken May 7th at Eldorado Canyon, but today we’ll have some fresher ones from Red Rocks, May 15th.

Besides the abundant prickly pear, the foothills offer these two ground-hugging cacti. They can be tricky to tell apart, so let’s take a closer look.

Most common is the “hen and chickens” or “green pitaya,” Echinocereus viridiflorus. (The species name means green-flowered.) It is more likely to grow tall (maybe 4-6 inches) and cylindrical than the second one shown here, and the spines tend to congregate on vertical ridges.

Flowers are just over an inch in diameter, to give you a sense of scale here.

Less often seen, in part because it can be so cryptic, is the nipple cactus, Coryphantha missouriensis. Short and compact, it actually withdraws into the ground a bit during the winter, making it even harder to spot. When in bloom, though, its yellowish flowers give it a little more distinction. The spines occur at the tips of protuberances, hence the name “nipple” cactus. In recognition of this feature, the genus was originally called Mammillaria. A similar species (C. vivipara) has pink flowers and is more unusual in our area.

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