PERIODICAL LITERATURE 329 



covered buds, and deciduous species with covered buds can be distinguished; (b) 

 According to size, since this is determined by the relation between the plants and 

 the humidity of the environment: (i) mcgaphanerophytcs, with a stature over 

 30 meters; (2) mcsophanerophytes, 8 to 30 m. ; (3) microphancrophytes, 2 to 8 

 m., and (4) manophancrophytes, less than 2 m. high are distinguished. 



"Chamcuphytes include those plants with their buds or shoot-apices perennat- 

 ing on the surface of the ground or just above it (not exceeding 25 cm.), so that 

 in countries with snow they will be protected in winter, while in other countries 

 with a dry season some protection will be afforded by plant remains. The buds 

 are better protected than in phanerophytes. The chamaephyte types include (i) 

 active chamaetypes, with shoots diageotropic and persistent throughout their 

 whole length ; (2) passive chamaephytes, with weak stems which lie on the 

 ground; (3) suffruticose chamasphytes in which the perennating parts remain on 

 the surface of the ground after the herbaceous parts have died away on the ap- 

 proach of the critical season; (4) cushion plants. 



"Hemicryptophytcs have their dormant buds in the upper crust of the soil, 

 just below the surface; the aerial parts are herbaceous and die away in the crit- 

 ical period, so that they form an additional protection to the earthbuds. The 

 perennating parts may be long or short, laterally extended or forming compact 

 root-stocks; hence, the group includes a large number of our native woodland 

 and hedgerow species and many rosette or half-rosette species. 



"Cryptophyfes includes plants with their dormant parts subterranean in the 

 case of geophytes, with bulbs, rhizomes, tubers on stem, and root and root-buds. 

 Another division is ch'^racterized by semi-aquatic dormant buds, helophyfes and 

 hydrophytes. The helophytes, or marsh-plants, do not include all so-called marsh 

 species, but only such cryptophytes as have their buds at the bottom of the water 

 on in the subjacent soil. The hydrophytes have either perennating rhizomes, 

 etc., or winter-buds. 



"Therophytes, or plants of the favorable season, live through the unfavorable 

 season as seeds ; hence, they are annual plants. They are characteristic of 

 deserts and of regions under high cultivation. In temperate regions, two divi- 

 sions are recognized; (a) summer-flowering annuals, (fc) winter-flowering an- 

 nuals, which pass through the winter in a vegetative condition." 



In the majority of his analyses, Raunkiaer uses the following ten 

 life-forms : 



1. S = Stem-succulents. 



2. E = Epiphytes. 



3. MM = Megaphanerophytes and mcsophanerophytes. 



4. M = Microphancrophytes. 



5. N = Nanophaneropliytes. 



. 6. Ch = Chamsephytes. * 



7. H ^ Hemicryptophytcs. ^ ''"" "^ 



8. G =: Geophytes. 



9. HH = Helophytes and hydrophytes. 

 10. Th = Therophytes. 



Such analyses are termed biological or phyto-climatic spectra. The 

 basis of comparison is the normal spectrum, which is based on careful 

 studies of from 400 to 1,000 representative species. 



