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Tue, Oct. 15

Native Plants of the Southwest (43) - San Tan Regional Park, AZ

San Tan Park

San Tan Park

Just one indicator of a healthy ecosystem is the status of the young. There are many juvenile Saguaro cacti in the Park. If it is reproducing, it's in good shape and that speaks well of the overall health of the natural environment. Spring would be the best time to see wildflowers, but fall and winter offer ideal hiking conditions: clear and cool.

There are great new facilities, educational programs, adequate parking, restrooms, and water at the trailhead. It is $6/vehicle to enter the Park. With all the development in the southeast part of the Valley of the Sun, there is still plenty of solitude, gorgeous desert vegetation, and the chance to do some real exploring.

Find this hidden Park from the town of Queen Creek. From the south side of Queen Creek at the intersection of Ellsworth and Empire, continue south on Ellsworth, which curves east, becoming Hunt Highway. After 1.4 miles, turn right on Thompson Highway. You are now going south. Go two miles to Phillips Road and turn right (west) for a mile to the Park entrance.

There are many trails in the Park, some 20 miles total. The loop I recommend begins by heading west on Goldmine Trail, then turns north. Within a mile you'll pass the intersection with the Littleleaf Trail. Continue north. As you approach Goldmine Mountain, you'll come to another intersection with San Tan Trail. Turn left, southwest, and head for the Hedgehog Trail, past a small hill. Turn back north toward the Park entrance for a total of about six miles. Topo Map: Chandler Heights. quad. 7.5'

One cactus, two vines, and one tree constitute the plants I highlight here. Technically, the cactus is a tree too. But who wants to get technical? The plant families represented are well known with one exception, the Malpighiaceae, a tropical family with only two species in Arizona. The other families, Cactus, Milkweed, and Pea are well known and economically important worldwide. Families are made up of individuals with shared characteristics. Learn these individuals by sight and remember the shared characteristics to more easily learn new members of the same family as a "familiar face" on your next hike. Landscape literacy is a collective exercise in paying attention to the world around you, its sights, sounds, and smells. The feelings and knowledge you gain will add to your confidence and enjoyment throughout your life.

Chainfruit Cholla, Cylindropuntia fulgida (Cactus Family)

I asked my teenage son to identify this cactus as we hiked through the Park this past weekend. I routinely test his plant knowledge when we hike together. He is getting pretty good at recognizing key elements of the Arizona Flora. He responded with a tentative tone, "Jumping Cholla." True, Chainfruit Cholla is one of the jumping cacti, even though it does not actually jump. The jointed segments making up its structure easily break off the main plant to start a new plant. They often lay scattered about on the ground. The specialized spines, glochids, easily catch a passing person or animal so that it seems like they jumped on the unwilling carrier. Rather, the walker got a little too close without realizing it and the piece of the plant that was just sitting there with its "thumb" in the air, hitched a ride on your shoe. A segment of the main plant might also break off as your leg brushes against it as you pass. Hence, it is easy for people to think the cactus jumped, because once it is on you it is difficult to get it off. I have helped several individuals, frozen in fear and pain, with tears in their eyes and blood running down their leg, free themselves from these spiny passengers. A comb is the best tool to do the job without getting more spines in your fingers or hands. One difference between this "jumping cactus" and Teddybear Cholla, the other "jumping cactus," is the chain of fruits you find on Cylindropuntia fulgida. These segmented cacti are covered with growing points called areoles. The fruits bear new flowers from these areoles, which mature into more fruits. These fruits persist one year to the next so that they form chains hanging from the main plant. The mature plants may reach a height of more than two meters, so there is plenty of space to hang around, waiting for an unwilling carrier to happen by so they can hitch a ride on their way to a new home. I hope it's not you, but if it is, have your comb ready.

Fringed Twinevine, Sarcostemma cynanchoides (Milkweed Family)

I love milkweeds, probably because they are peculiar. Other plants have milky sap so this is not the peculiar character I think of, though it is less common than other types of sap running through the vessels of plants. The pollination of the Milkweed Family is quite odd. Most flowers than insects pollinate, pass along pollen via their insect carrier one grain at a time. True, more often than not, the cooperative insect gets covered with pollen so that it actually carries quite a few pollen grains each time it visits a different flower. But milkweeds pass along a whole sack of pollen to their insect partners in the business of sexual reproduction. It's a little more risky to send off such a large and precious bundle on the head or leg of a single visitor. Losing a single grain is not a big deal but to lose a whole sack is another matter. Also, the seeds found in each fruit are quite numerous. Attached to each seed is a tuft of silky hair designed to send the seed aloft on air currents to find a new home. What an interesting combination of reproduction elements, insects to transfer pollen and the wind to transfer seeds. Fascinating. The flowers are often beautiful and in the case of Fringed Twinevine, they are clustered along stems that clamber over and atop any convenient object, such as a fence, another plant, or a stump, anything to get a little higher to attract a flying insect and to send those seeds aloft on the slightest air current. The flowers of Sarcostemma are purplish with prominent white elements. They are only about a cm across and star-like in symmetry. The fruits are brownish, plump, and pod-like. The leaves are arrow-shaped and dark green. Lovely to look at and curious to think about all that is going on behind the scenes of plant reproduction.

Slender Janusia, Janusia gracilis (Malpighia Family)

This plant is easy to recognize due to its combination of a few distinctive characteristics. First, it's a vine and vines are few and far between in the desert. Second, it lacks milky sap. It's not always what you have that sets you apart. It could be what you lack. In this case, milky sap. Third, the flowers, though small are notable. The bright yellow petals, number five and each petal is clawed or spoon-shaped. They have a radial symmetry, and the petals are separate from each other. Therefore, they do not form a tube. They stand out like the sun. Fourth and finally, the fruits are winged like a Maple, only Janusia has three wings instead of two. The wings are also reddish and persist for some weeks so you are likely to see them when the flowers are long gone. Hiking in the desert is best when it cools off and that's when you'll see the fruits. The flowering season runs all the way from April through October. So, before it heats up look for the sunny flowers and after it cools off, look for the maple-like winged fruits scattered along twining stems. Once you see it, you'll not soon forget it. You just have to slow down and notice it in the first place. This is difficult for some, but worth pausing to notice the beauty all around you on your next hike.

Ironwood, Olneya tesota (Pea Family)

There are quite a few nursery plants in the desert, but Ironwood is the most renowned. Ironwood trees can live for many years, collecting litter all the while. In that litter are seeds, feces, and a much higher degree of organic matter than the surrounding soil. There is also a good deal of shade and that is a rarity in the desert. Add it all up: organic matter, nutrients, shade, more than average moisture levels and you have a nursery. Plants and animals find that life is a little better under an Ironwood tree than anywhere else in the vicinity. A little better in the desert, where extremes in temperature and solar radiation matter, might mean the difference between life and death. Additionally, as the name implies, Ironwood is very heavy or dense. According to Epple, in A Field Guide to the Plants of Arizona, one cubic foot weighs 66 pounds. The flowering period for Ironwood is narrow, May and June. But it is grand, none-the-less. I was driving back into Phoenix after a climb on Pinnacle Peak many years ago and I had to stop and take a closer look at the huge display of purple flowers on the 30' tree at the side of the road. Absolutely stunning in flower, it is also recognizable the rest of the year with its evergreen, grayish leaves. It is armed with a pair of slightly curved spines at the base of each compound leaf, so approach it gently so it won't tear you apart. It doesn't mean to be vicious, but its leaves are browsed by grazing animals, so until it gains enough height to place those leaves out of reach, it puts up a strong defense or deterrent to being eaten. You might do the same. I know I would, since I couldn't run away. A tree must stand there and take whatever happens to come its way. That's one reason I like plants so much. They don't run away. I see them on every hike. Some are familiar faces and there are always new botanical discoveries to enjoy on every hike, if we take notice of them.

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