In this file you are on the text layer. See the file “Graphics Layer” for an example of the graphic tools and the graphics layer.
Graphics as a character:
When you are in the text layer, you can type and edit text. You can paste graphics created in another application, copied from the scrapbook or created on the graphics layer within Nisus and copied to the clipboard. When pasted in this way, the graphic behaves like a character, moving with the text. You can even paste such a graphic into the Find/Replace dialog box and search for another graphic. With the Find Text Only menu command checked, you can find any character graphic. If you check “Find Text Only” off, you will find any character graphic which has exactly the same rectangle size.
• Experiment with the sample below:
Select the character graphic below (the cactus), choose Cut or Copy, place your insertion point anywhere in the text and Paste.
Note that the arrows and the associated text are on the graphic layer. Choose Graphics Ruler from the Display submenu of the Tools menu to get to this layer.
PLANTS ADAPTED TO THE DESERT
The cactus is a plant without leaves. In most plants, the leaves are the site of photosynthesis, the "factories" where the sun's energy is used to make food. Why then do cacti and many other desert plants lack leaves?
Though leaves help a plant, they can also do it some harm. Their microscopic openings allow gasses—including water and vapor—to enter and escape. During a single summer day, a large tree may lose several tons of water. Usually, this is not a problem for plants, but in the desert, water loss can be deadly.
For most of the year, the ocotillo, a common North American species, is a thorny bundle of brown, wand-like branches, each about 10 to 20 feet long. Soon after the spring rains—if they come—brilliant red flowers emerge from the end of wands (they give the plant another of its common names—candlewood). Within a few days, leaves emerge from the stems; their small size minimizes water loss. By early summer, the leaves have fallen.
Like the ocotillo, the creosote bush (its Spanish name means "little stinker") has small leaves that remain on the plant for only a short time. But the creosote bush goes the ocotillo one better—in a severe drought, it loses twigs and even branches. In addition, the creosote bush poisons neighboring plants—a substance secreted by its roots kills other seedlings, which might compete with it for water. Creosote bushes often grow evenly spaced, as if they were planted in an orderly fashion by human beings. The spacing is a living record of the climate; the heavier the rains were in the preceding years, the closer together the bushes grow because the moisture washes the root poison deeper into the soil. (Liquid creosote, the familiar wood preservative, is made mainly from coal tar, not from these shrubs.)
Cacti have spines, not leaves. Because the spines have no openings, water loss is not a problem. In addition, the spines are believed to provide some shade for the cacti and to trap and insulating layer of air. And, of course, the spines also serve as a deterrent to plant-eaters.
A cactus's outer skin is a tough, waxy coating that further protects the plant from water loss, almost as if it were covered with plastic wrap. Photosynthesis takes place in the stem of the cactus, which also stores water. Cacti are included in a group of plants called succulents, which are juicy and retain water. The moisture in many succulents takes the form of a gummy sap. (The plant can nevertheless be used as a water supply for thirsty travelers, if the pulpy interior is pulverized.) The sap may dry out if the plant is wounded, creating a plastic-like "bandage" that lessens water loss. Long after a cactus is dead and gone, these cup-like formations—called desert shoes by some Indians—may remain on the desert floor.
