IGO PROCEEDINGS OF THE ACADEMY OF [1892. 



CONTEIBUTIONS TO THE LIFE-HISTORIES OF PLANTS, NO 7. 

 BY THOMAS MEEHAN. 



On THE Vitality of some Annual Plants. 



Prof. Tbeo. Holm, of the Smithsonian Institution, is the aiitlior 

 of a suggestive paper under this title.' He notes a number of spe- 

 cies generally recognized as annual which frequently furnish bien- 

 nial or ])erenniai individuals. Such observations are especially use- 

 ful, for it is deviation from general rule that furnishes us with keys 

 to unlock the great treasure-box of nature's secrets. If we can show 

 that annuals are not always annuals, but sometimes become peren- 

 nials, we have the opportunity to watch the process, and learn as the 

 work goes on. 



Horticulturists must have long known, without giving the matter 

 serious thought, that annuals become perennials under some circum- 

 stances. Petunias, Gaillardias, and indeed I can think of no annual 

 plant of any kind whatever, that the horticulturist cares to preserve, 

 that he can not preserve from cuttings when he so desires. Even in 

 the case of those annuals which throw up only a single flower scape, 

 he plucks off the flower head before the flower buds expand, cuts up 

 this flower stem into sections, and raises plants which will live 

 continuously for many years, if annually treated in the same way. 

 Annuals or biennials will live for many years if the flower buds are 

 plucked out as soon as they appear. The author of this paper has 

 seen mignonette six years old that had been treated in this man- 

 ner. Annual parts of perennial plants also live over when propa- 

 gated in the same way. Perennial ])hlox, hollyhock and similar 

 plants are raised from sections of the flower stems which have had 

 their flower heads taken out a few weeks before they were cut into 

 the segments desired. 



It is worthy of remark just here, that few plants except those 

 which we distinctly recognize as ligneous, have perennial parts. 

 The potato lives only through the tubers it makes annually, and 

 even the strawberry plant will be found to be dead below the addi- 

 tion of the past year. Gladiolus, lilies, many terrestrial orchids, 

 and numerous other plants, only live over through the additions of 

 the preceding year. The older portions die after new portions have 



1 American Journal of Science, Vol. XLII, Oct., 1S91. 



