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Horticulture Principles and Practices

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FIGURE 14–1 Succulents<br />

can grow under dry <strong>and</strong> marginal<br />

environments. (Source: Tony<br />

Souter © Dorling Kindersley)<br />

FIGURE 14–2 Stem succulents:<br />

(a) Columnar cactus represented<br />

by Pachycereus schottii;<br />

(b) Barrel-shaped cactus represented<br />

by barrel cactus. (Source:<br />

For (a) © Dorling Kindersley, (b) Jeremy<br />

Hopley © Dorling Kindersley)<br />

(a)<br />

(b)<br />

is the presence of thorns (spines), which when removed do not cause sap to be exuded.<br />

If sap, clear or milky, exudes upon removal of a spine, the plant is definitely not a cactus.<br />

Examples noncacti thorny succulents are hawthorns, black locust, roses, <strong>and</strong> raspberry<br />

brambles.<br />

Succulents are geographically widely distributed, but occur mostly in frost-free<br />

regions with low rainfall. They are found in mostly arid regions <strong>and</strong> less frequently in<br />

the humid forests, but rarely in the driest desert. Succulents are tolerant of poor <strong>and</strong><br />

shallow soils.<br />

452 Chapter 14 Growing Succulents<br />

14.2 CATEGORIES OF SUCCULENTS<br />

Any plant with fleshy leaves or stems is considered a succulent. Succulents may be<br />

divided into two broad categories based on form:<br />

1. Stem Succulent—The most conspicuously adapted plant part is the stem. These<br />

species have fleshy stems that contain chlorophyll <strong>and</strong> hence have the capacity<br />

for photosynthesis. The stems may be columnar or barrel shaped (Figure 14–2).

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