THE STEM 63 



season is therefore not lost, or lost only with extreme 

 slowness, in the dry period. 



100. To all more or less flattened stems thus modified 

 to serve as foliage (e.g. Asparagus, Muhlenbeckia, Prickly 

 Pear) the name phyllocladia (singular phyllocladium) has 

 been given. 



101. The longevity of trees. The duration of the stem is the 

 duration of the plant, for the stem is the permanent seat of life in 

 plants, the part from which new organs arise and new shoots of the 

 same individual are produced. When the stem dies, the plant as an 

 individual perishes. 1 In considering stems, therefore, the length of 

 life of plants is naturally suggested. Annual, biennial, arid perennial 

 are terms already explained in the chapter on the root. Many of the 

 perennial herbs, such as the acaulescent kinds, live for a comparatively 

 long time, without forming any considerable quantity of wood or 

 much increasing the length of the stem, probably for a dozen or a 

 score of years. 2 The continuance of life in shrubs and trees in 

 these cases is often great compared with that of human life, and in 

 not a few cases, is exceedingly great, so that single trees still living are 

 known to have sprung from the seed long before any but the oldest 

 of existing nations came into being. "The celebrated Lime of Neu- 

 stadt in Wiirtemberg is between eight hundred and one thousand 

 years old ; the age of the Fir of Beque is estimated at twelve hundred 

 years, and a Yew in Braburn (Kent) is at least as old." 3 John Muir 

 cites two cases of Sequoias, the Big Trees of California, determined 

 by the annual rings as being respectively thirteen hundred and twenty- 

 two hundred years old ; though the latter was " not a very old-looking 

 tree." " Under the most favorable conditions these giants probably 

 live five thousand years or more, though few of even the larger trees 

 are more than half as old. I never saw a Big Tree that had died a 

 natural death ; barring accidents they seem to be immortal, being 

 exempt from all the diseases that afflict and kill other trees. Unless 

 destroyed by man, they live on indefinitely until burned, smashed by 

 lightning, or cast down by storms, or by the giving way of the ground 

 on which they stand. . . . The colossal scarred monument in the 

 King's River forest mentioned above is burned half through, and 



1 Though, as has been stated, the roots even when cut away or when 

 the stern is removed may produce new buds. But these are out of the 

 ordinary course of events, and in a sense result in new individuals, not 

 the continuance of the old. 



2 The only available data seem to be casual observations. The sub- 

 ject is an excellent one for definite observations and record. 



8 Strasburger, "Text Book of Botany," 1898, p. 239. 



