SJSU Campus Botany Biol20 s2018 PDF

Preview

Summary

poffenroth...

Description

SJ S U C AM P U S B O T ANY A G UIDE TO SOME I NTE RESTING P LANTS ON CA MPUS

During this lab you will be learning how to identify some of the plants found on the San Jose State University campus. Refer to the pictures and illustrations provided. The plants in the lab are labeled with colored flagging and are also marked on a campus map at the end of the guide. Questions are asked to direct your observations and help you identify the important characters of the plants. You may not be able to answer all of the questions at first, at least not by yourself. Think about them, and discuss them with other students and your lab instructor.

1. Start with the three needle leaf trees across the driveway from the SE doorway to Duncan Hall. On all three you will see needle-like leaves growing in bundles called fascicles. How many needles are in each fascicle? These trees have cones instead of flowers or fruits, so they are conifers (cone bearing), which is a group of gymnosperms (naked, exposed seeds, as opposed to being enclosed in a fruit). Most conifers are evergreen. Broad leaf angiosperms (flowering plants) can be either deciduous or evergreen. The Coulter Pine, nearest San Salvador Street, has the heaviest cone of any pine species. Loggers and wildland firefighters working in its native range, the mountains of central and southern California, sometimes refer to it as the ‘widow maker’. The Canary Island Pine, on the left, is one of the most commonly planted pines in California although it is native to the Canary Islands off the coast of Morocco.

2. SKIP This plant was removed in 2017 during the project to drill a new water well for SJSU’s main campus. This tree is the single California species of a genus that is much more common in the Eastern Deciduous forest. This plant, the California Buckeye, is drought deciduous, which means it drops its leaves and is dormant during the hot dry summers found throughout much of California. It was an important backup food source for Native Americans. It supplemented their diets in years when the acorn crop was poor. You will see examples of this plant in a few weeks, in Alum Rock Park.

3. Continue down the driveway 50ft to the tree on the right, which is a bushy tree with dark green, somewhat elongated leaves. Is the tree deciduous or evergreen? How can you tell? Alternate or opposite leaves? Crush a leaf and smell it. Odor can be useful in identifying plants. The California Bay Laurel is an important tree in the coastal forests of California. The fruit, which looks much like a small avocado, is high in fats and is an important food for wildlife. Some Native American tribes used the leaves of this tree to treat headaches by rolling up a leaf and placing it in one nostril. The aromatic oils (a group of chemicals called monoterpenes and sesquiterpenes) that give the leaves their strong odor have microbicidal and insecticidal activity. An extract of the leaves was used to treat head lice.

4. Across the driveway from #3, alongside Duncan Hall, are two broadleaf trees. Is the plant deciduous or evergreen? How can you tell? Are the leaves alternate or opposite? (Look where the internodes are most elongated) Notice the fruits (the spherical structures). They are aggregates of follicles. This tree, the American Sweetgum, is an important tree in the forests of eastern North America. In California, it is one of the most common street trees and is planted for its vibrant fall color.

5. To the right (north) of #4, next to DH, is a small tree with roundish, tough, somewhat spine-tipped leaves. Note also the leaves are somewhat cup-shaped. This is a native Californian species, and the toughness of the leaves is an adaptation to living in our Mediterranean climate. How is leaf toughness advantageous? The Coast Live Oak is the most important coastal oak species from San Francisco to San Diego. It was the staple food for Native Americans and continues to be a critical food for native wildlife. Before eating the nutritious acorns, the Native Americans first had to leach them in running water for several days to remove toxins.

6. Back across the driveway, near the comer of the parking garage, are two trees with scaly bark and interesting leaves. Examine the leaves closely. Are they simple or compound? Alternate or opposite? What is distinctive about their leaflets? The Catalina Ironwood has two subspecies, both of which are endemic to the Channel Islands (i.e. they live nowhere else in the world). This subspecies occurs only on San Clemente, Santa Cruz and Santa Rosa Islands, although there are fossils from mainland California and Nevada, which indicate that it was once more widespread.

7. Enter the Botany Garden from the back (east end). Stop at the large shrub/small tree immediately on the left. It has roundish, very toothed leaves. Are the leaves deciduous or evergreen? Note the coloration of the leaves, especially the undersides. Crush a leaf and smell it. Do you note a hint of almond? Mesophyll cells in the leaves of this species contain a group of chemicals called cyanogenic glycosides. When you damaged the leaf by crushing it, an enzyme cuts off part of the glycosides, releasing a minute amount of poisonous hydrogen cyanide gas, which smells like almonds. Why might some plants have leaves that release toxic gas when damaged? The fruits of this native plant, The Holly-leafed Cherry, are dark red, fleshy, and have hard pits inside. They are an important food for birds and mice.

8. Continue to the very large tree where the path divides. This species normally occurs along streams and rivers (riparian habitat), so it does not grow vigorously here. Leaves simple or compound? Pinnate or palmate? Leaves alternate or opposite? There may not be any fruits on this tree, the Oregon Ash, but if there were they would be samaras, meaning they have winged extensions. Ash trees are valued by woodworkers for a variety of purposes. It is commonly used

for wooden salad bowls because the wood does not have a distinctive taste

9. This plant grows on the branches of the Oregon Ash tree (#8) If you look carefully up at the branches in the Oregon Ash tree, you may see some clumps of stems and leaves that look different from the rest of the tree. This is a separate plant, American Mistletoe, that grows as a parasite on the Oregon Ash. The mistletoe grows specialized structures called haustoria that allow them to tap into the vascular system and absorb water and nutrients from their host.

10. Continue on this path toward the front of the garden, and stop at the light green shrub on the right, where the two paths meet. What is the leaf position? Note the leaf color and orientation relative to the ground and the stem. Why might these be advantageous in the desert (where this plant occurs naturally)? Jojoba occurs in the California and Mexico deserts. This plant produces a liquid wax in the seeds, which is very useful in the cosmetic industry and as a high quality machine lubricant. This species has separate male and female plants, and the large bush here is a male plant.

11. Continue to the right (north) to the small tree in the comer of the garden. What is the leaf venation? What is the leaf shape? Are there fruits hanging on the tree? If so, describe them. Western redbud is a chaparral shrub or small tree that gets its name from bright pink flower buds that give rise to brilliant displays of pink flowers. It is in the pea family and the flowers mature into fruits that are easily recognizable as pea pods (they are not edible). Around campus, and throughout San Jose, the closely related Eastern Redbud is commonly planted. That species has a leaf with a pointed tip whereas Western Redbud has a rounded tip.

12. If you turn toward the University House you will see toward the left and right a couple of large palm trees. There are also rows of palms on the other side of the house and on both sides of the Paseo toward 4th Street. The palms by the University House have large pinnately shaped leaves whereas those across and along the Paseo have palmate leaves. “Pinna” is a word meaning feather, so pinnate-leaf palms are called feather palms. The great majority of palms are feather palms. The only California native palm is the Washington fan palm, found in the deserts of southern California. This is the common fan palm planted along SJSU’s Paseos. It occurs in desert oases and was inspiration for the names of cities including Palm Springs and Palmdale in southern California.

13. Continue past the house to the Paseo. In the middle of the Paseo on the right is a small grove of trees with somewhat large, lobed leaves, and light colored bark. Note the arrangement of the leaves. Are they simple or compound? What terms describe their shape? Compare these leaves with those of tree #16. These are London Plane trees. They are hybrids between a sycamore from eastern North America and another sycamore from Europe. The hybrid was developed in the 1700’s and was heavily utilized then (as it is now) in urban areas because it is highly tolerant to pollution. See tree 16 for further discussion.

14. Continue under the overpass part of Uchida Hall toward the quad. In the comer area on the right side of the building are a couple of large trees with small, scaly branchlets and small, round seed cones. Find an individual leaf. (This is tricky) What would be the term describing the leaf type? Are the leaves opposite or alternate? How many leaves at a node? Hint: you might break a small branch (linear segment) and examine the leaf tips from the broken end. A hand lens would be helpful. This is an extremely rare species in nature. The only population of the Monterey Cypress occurs in Point Lobos State Park, on the Monterey Peninsula. Because of its charismatic form, it is widely grown throughout California and the world as an ornamental.

15. At the left (west) corner of the chapel is a very large conifer that many of you may recognize. It has short, flattened needle leaves. Look around for a seed cone. There are many smaller pollen cones on the tips of the branches. This is the Coastal Redwood, the state tree of California. It occurs from around the California/Oregon border to a little south of Monterey. Currently, this species is the tallest in the world (>400 ft.). Although this individual is quite large, much larger ones can be seen in Great Basin State Park. Redwood is an excellent building material and most redwoods seen today grew up subsequent to extensive logging during the development of the Bay Area after the gold rush of the mid-1800s.

16. The next tree also has lobed leaves, but they are palmate rather than pinnate. The broad, palmately lobed leaves look like the one on the Canadian flag. Are the leaves alternate or opposite? You might want to compare closely these leaves with those of #13. You should also find fruits, which are usually in pairs and have elongated wings. This is the most common native Maple in California, the Bigleaf Maple. Maples, including the Sugar Maple which produces the sap used in maple syrup, are much more common in the central and eastern parts of the continent. Like it’s eastern relatives, Bigleaf Maple often has very attractive fall color.

17. Across the path to the east is a large, grey colored conifer. Note the clusters of needles on short shoots along the larger branches. Would you consider these fascicles? Why not? Look for any seed cones and pollen cones. The seed cones are different than pine cones in that they sit upright on the branches. This is the Atlas Cedar. It occurs primarily in the Mediterranean region and no members of its genus are native to North America. A close relative with longer needles and darker green foliage, the Cedar of Lebanon, is also a common ornamental in California. The distinctive color of this tree is caused by the waxy cuticle that is produced by its leaves to prevent water loss.

18. Turn around and take the path to the west, alongside the quad. Stop at the tall conifer on the left, just before you get to the chapel. This tree looks similar to #15, but different. What is the difference? Look for cones. How do they compare with #15? This tree, the Dawn Redwood, is common in the fossil record throughout North America and China, but is extremely rare as a living species. It was not discovered by scientists until 1946 when it was found growing at monasteries in China. It is closely related to the California redwoods and to the Bald Cypress, which grows in swamps in the southeastern US. Unlike most gymnosperms, this species is deciduous.

Plants #19-23 are found around the Faculty Office Building

19. Sword fern (Polystichum munitum) [above, left] This fern is a common understory species in the Coastal Redwood forests of California and is a beneficiary of the fog-drip that is generated by the redwoods. Like other ferns, the developing leaves of this fern begin as ‘fiddlenecks’ (technically croziers) that unfurl as the leaf matures. Ferns reproduce by spores, which are housed in collections of sporangia called sori. Look for the sori on the undersides of the leaves. 20. Tree fern (Dicksonia antarctica) [above, right] Although these individuals are small, when mature they can become trees as tall as 50 feet. Ferns do not produce true wood. Their trunks are formed from many bundles of vascular tissue and supporting fibers aggregated into a single trunk. Tree ferns very rarely branch and instead have a single columnar trunk with the large leaves borne directly on the trunk.

21. Giant Dioon (Dioon spinulosum) This native of Mexico can become a tree to 50 feet tall. On the surface, it resembles both a tree-fern and a palm. It has a single trunk that is sheathed in old leaf scars rather than the bark typical of Eudicots and Gymnosperms. Cycads are Gymnosperms. When they are in reproductive condition, this is very easy to determine because the seeds are typically borne in large, prominent cones. Unlike other Gymnosperms, however, cycads have pinnately compound leaves. Leaf texture is a good way to separate cycads from palms and tree ferns. Cycads have very tough, leathery leaves whereas palms and tree ferns have leaves that are much more thin and fibrous. Cycads are a very ancient lineage, but many of the species, as determined by genetic analyses, are actually quite young. Because they are highly prized by collectors for their unique morphology, most Cycad species are threatened or endangered in the wild due to extensive poaching. For #22-23 you will need to look on the ground behind the hedges where the soil stays damp.

22. Crescent-cup Liverwort (Lunularia cruciata) [above, left] This is a common weedy liverwort that lives in irrigated flower beds throughout the world. It reproduces with via asexual propagules that are held within crescent-shaped receptacles. These crescent shaped receptacles give rise to the genus name Lunularia, which means ‘Moon-shaped’. This is one of two fairly common weedy liverworts on campus. The other, Marchantia polymorpha, has circular receptacles bearing propagules rather tan crescentshaped receptacles. 23. Twin-tooth moss (Didymodon vinealis) [above, right] This is a native moss that is extremely drought tolerant. It is common in many plant communities and does very well in urban environments. Look closely and you can seed that the plant, is made up of individual stems and leaves. The name ‘vinealis’ means wine-colored and refers to the maroon coloration of dried plants, especially in the summer.

24. Continue to the grassy area east of Morris Dailey Auditorium and south of Clark Hall (by the statues of Tommie Smith and John Carlos from the 1968 Olympics) and examine the large tree with the deeply furrowed gray bark. Describe how the bark of this tree differs from other species you have seen. This tree, the Cork Oak, is native to southern Europe and northern African. The bark from this tree is used to make cork for wine bottles, flooring, etc. A skilled worker can peel off the bark without damaging the living cambium layer beneath. Like all oaks, the fruit of this tree are acorns. Here is a video of cork being harvested from a Cork Oak in Sardinia: https://www.youtube.com/watch?v=bqF3SGFigdY

25. Head south, between Dwight Bentel Hall and the Central Classroom Building. Just south of the Central Classroom Building is a large tree with deeply lobed leaves. Note how the bark of this tree is different from the tree you examined previously. Bark can be a useful feature for identifying trees. The Valley Oak is native to California. Members of this species can live for over 600 years and grow to be among the tallest angiosperm trees found in North America. The fruit of this species is an acorn, and was a very important food source for Native Americans living in California’s Central Valley. In some cities in the Central Valley, ancient individuals can still be found, but most were removed as land was converted for agriculture.

26. Head southeast along Paseo de Cesar Chavez toward 7th street and the corner of Sweeney Hall. On the right are a couple of trees, familiar to some, with grayish leaves and either green or dark fruits. Leaf position? Are these trees deciduous or evergreen? Note the slightly in-rolled margins. What is the significance (advantage) of the gray coloration and the hairs on the underside of the leaf? These are Olive trees. Unlike most olives planted ornamentally today, these individuals are female and produce fruits. Younger trees planted around campus are mostly male. Olives are among the oldest cultivated plants and are native to the Mediterranean region. They are also a major crop here in California because of our similar climate.

27. Continue along 7th street to the pathway between Sweeney Hall and South Garage. On the right, is a tree with fan-shaped leaves. The leaves are distinctive, arising on short shoots from the main branches. You may be able to reach some on the lower trunk, or find some on the ground nearby. Examine the venation closely. Is this tree deciduous or evergreen? This tree, the Ginkgo, or Pagoda tree, is native to China. A “living fossil,” this tree is not known to exist in any natural habitat, but has been cultivated for centuries in gardens and urban settings in China. It remains an important urban tree because of its tolerance of air pollution. In the fall you may see pinkish, fleshy structures that look like fruits. They are actually seeds with fleshy coats. This tree does not produce flowers or fruits, so is a gymnosperm, but one with broad leaves rather than needles. Since there are no cones, this gymnosperm is not a conifer. This tree is male and does not produce seeds. The ripened seeds on female trees are foul smelling (they contain the chemical butyric acid, also found in rancid butter and vomit. Most cities and parks prefer to plant male trees, which produce only pollen.

Want to learn about more trees on the SJSU campus? Check out the tour of trees on the San Jose State University campus created by Our City Forest: https://maps.google.com/maps/ms?msid=206683040831959829790.0004a26623c5c69d3dbfc&msa=0&ll=37.3361 39,-121.883349&spn=0.004771,0.00603

Lab created by Rodney Myatt. Revised by Lars Rosengreen (2014-2018) and Ben Carter (2016-2017)....