Spike. A cluster of sessile flowers along a central axis; an inflorescence. See figure G-7. 
						 
						
					
					
					Spiral topiary. See Topiary. 
						 
						
					
					
					Spore. A reproductive cell that has no embryo, as do seeds, but rather is a mass of protoplasm with a nucleus. 
						 
						
					
					
					Spreading. See Tree shape. 
						 
						
					
					
					Standard. Term describing: (1) a plant that grows from a single stalk but needs external support to stand alone; (2) a tree with at least 6 feet (1.8 m) of trunk before the first branch; (3) a shrub that is cleared of lower branches, and is trained to have a single stem from the base to the first foliage. See also Tree shape. 
						 
						
					
					
					Standard topiary. See Topiary. 
						 
						
					
					
					Stilt hedge. A hedge variation in which dense foliage is pruned above a base of bare branches. Also called pole hedge. 
						 
						
					
					
					Stone. Rock selected or processed for construction or some other use. 
						 
						
					
					
					Stone fruits. Members of the genus Prunus, all of which have a single pit (stone) surrounded by flesh. Examples: Plums, cherries, peaches. 
						 
						
					
					
					Strata. (Sing. stratum.) Geologically, the layers, usually horizontal, of rock formations. 
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					Succession. The development of plant communities after the virgin habitat and flora have been disturbed. 
						 
						
					
					
					Succulent. A plant with fleshy stems and leaves adapted to retain water. Example: Aloe. 
						 
						
					
					
					Tapestry hedge. A hedge made by intermingling two or more types of plants. 
						 
						
					
					
					Tender. Term describing plants that will not survive a freeze. Example: Impatiens. 
						 
						
					
					
					Toadstool. The common name for the fruiting body of a fungus with an umbrella-shaped cap. 
						 
						
					
					
					Tomentose. Term describing a plant surface covered with short, soft, woolly hairs. Example: Salvia officinalis, common sage. 
						 
						
					
					
					Topiary. The art of training plants to grow in specific shapes (often object-oriented) by means of pruning and clipping. Standard topiary consists of a single unbranched vertical stem with pruned foliage usually forming a round single crown. The shape may also be achieved by grafting rather than pruning. Poodle topiary is a variation of standard topiary with multiple balls of foliage rather than a single crown. Spiral topiary is a variation of standard topiary with the foliage clipped around the single stem so that it forms a coil. The stem may be trained to grow in a corkscrew twist. Flat topiary consists of low hedges or other clipped plants that form level beds, for example, knot gardens and parterres. 
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					Tree. A perennial woody plant that has a strongly defined trunk with a head of branches, the crown or canopy. 
						 
						
					
					
					Tree shape. Term descriptive of branch direction and canopy growth. Some common shapes are columnar (taller than it is wide); conical; fastigiate (with branches that grow erect, parallel, and close together); globe; pyramidal, shrubby, spreading (develops with predominantly lateral branches); standard (having at least 6 feet [1.8 m] of trunk before the first branch), weeping. See figure G-8. 
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					Trellis. A framework used to support and direct vining and climbing plants. traditionally constructed in a diamond or grid pattern. 
						 
						
					
					
					Trifoliate. See Compound leaf. 
						 
						
					
					
					Tropical. Term describing plants that will not survive below 40  45 degrees F (47 degrees C). 
						 
						
					
					
					Twig. The individual unit of new growth of a woody plant.  
						 
						
					
					
					Twining vine. See Climber. 
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