CHAP, ii GROWTH-FORMS 7 



We adopt the following sub-division : 



I. MONOCARPIC HERBS, 

 which include the following groups : 



(a) Aestival annual plants. The whole cycle of life is completed 

 within one vegetative period, varying from a few weeks, as in ephemeral 

 desert-plants, to several months. Shoots foliaged with elongated inter- 

 nodes (monocyclic). No vegetative organs of storage. The unfavourable 

 season passed in the form of seed. 1 Adaptation to dry climates and 

 localities, and to disturbed soil (littoral sand, cultivated soil, and the like), 



(6) Hibernal annual plants. These germinate in autumn, and con- 

 clude their existence with the production of fruit in spring. Rosette- 

 shoots are usually prevalent. Otherwise like those belonging to the 

 preceding group (a). 



(c) Biennial-perennial (dicyclic, pleiocyclic 2 ) herbs produce in 

 their first vegetative period or in several successive ones rosettes of 

 leaves, and in the following period the flowering shoot, which usually bears 

 foliage. The foliage-leaves often live through winter. Buds open. Form 

 of the shoot as in (6). Reserve-food often stored in tuberous axial organs 

 (Beta vulgaris, Daucus Carota). Occurring in cold-temperate climates on 

 open soil, also as cultivated plants. 



II. POLYCARPIC PLANTS 



In the case of the polycarpic plants it is necessary to consider, first, 

 their adaptation to climate, and in particular the season unfavourable 

 to plant-life ; secondly, the vegetative season ; and, finally, the conditions 

 prevailing in regard to the soil, which Schimper terms edaphic conditions. 

 Of greatest importance is 



1. Duration of the vegetative shoot : lignified axes of trees, shrubs, and 

 undershrubs ; perennial herbaceous shoots ; herbaceous shoots deciduous 

 after a short period. 



And closely associated with this is 



2. Length and direction of the internodes : whether the shoots have 

 short internodes (rosette-shoots) or long internodes, and whether the latter 

 are erect (orthotropous) or prostrate and creeping (plagiotropous). 



3. Position of the renewal-buds during the unfavourable season [high 

 up in the air, near the soil, under the surface of the soil, or buried in the 

 soil (geophilous)]. 3 



Of less importance is 



4. Structure of the renewal-buds or of buds in general. All stem-apices 

 and very young leaves are protected by leaves ; this protection is accom- 

 plished in some cases merely by older foliage-leaves (open buds), in other 

 cases by specially differentiated protective organs, which are either 

 parts of foliage-leaves or definite bud-scales. This depends less upon 

 climate than upon the form of the assimilatory shoots ; short- jointed 

 shoots with leaves in rosettes usually have open buds ; long- jointed 

 shoots are more varied. These differences in the shoot are physiognomi- 

 cally important, not only in themselves, but because the former shoots 

 are branched little or not at all, while the latter are usually richly so. 



1 See Ascherson, 1866. * Warming, 1884. 



4 See the nomenclature in the paper by Raunkiar, 1905, 1907. 



