290 PLANT SOCIOLOGY 



V. HYDROPHYTES (water plants); all water plants other than plankton; Their 

 perennating organs are submerged in water during the unfavorable season; The 

 subgroups are: 



1. Hydrophyta natantia: free-floating water plants such as Letnna, Ceratophyl- 

 lum, Utricularia, Riccia, and filamentous algae like Spirogijra. 



2. Hydrophyta adnata: water plants anchored to the substratum, including 

 algae, mosses {Rhynchostegium rusciforme, Fontinalis), liverworts, mosses, 

 and fungi; 



3. Hydrophyta radicantia: aquatics with roots such as Potamogeton, Zostera, 

 Posidonia, Nymphaea, and Hippuris. According to Koch, this group 

 comprises: 



c. Hydrogeophytes such as Potamogeton lucens, Zostera, etc; 



b. Hydrohemicryptophytes such as Lobelia dortmanna and Isoetesi 



c. Hydrotherophytes such as Najas and the Potamogetons of the Pusillus 

 group; 



VI; QEOPHYTES (earth plants): plants with the perennating organs (buds, 

 mycelia) buried in the substratum and therefore but little exposed to the influence 

 of the unfavorable season. The subgroups are: 



1. Geophyta mycetosa (fungus geophytes): fungi with survival through 

 myceha in substratum; nourishment heterotrophic; Including: 



a. Tuberous fungi : fruiting bodies subterranean as in Tuber i 



b. Aerial fungi: fruiting bodies aboveground; 



2. Geophyta parasitica (root parasites): plants with their perennial organs 

 subterranean, sunken in the host such as ConophoUs, Rafflesia, and 

 Orobanche: 



3; Eugeophytes: divided into several groups (Fig. 148/ to h): 



a. Geophyta bulbosa (bulb geophytes): plants with underground storage 

 organs, such as root tubers (many Orchidaceae and LiUaceae); stem 

 tubers (Eranthis, Corydalis, Bunium, Cyclamen) or true bulbs (many 

 Lihaceae, Amaryllidaceae, and Iridaceae). At the beginning of the 

 favorable season the formation of leaf and flowering shoots begins. As 

 soon as the flowering stage is completed, the parts aboveground begin to 

 wilt and disintegrate. The plant withdraws again below the surface and 

 spends the imfavorable, usually dry and hot, season in a resting condition. 

 From the energy stored, it is able again to resume its life activity in the 

 fall or spring, to bloom and fruit. The bulbous geophytes therefore 

 are most abundant in warm, dry regions with a short vegetative period; 

 Their climatic requirements are similar to those of the therophytes. 

 bi Geophyta rhizomatosa (rhizome geophytes): plants with rhizomes that 

 are able to travel underground. They do not thrive on stony compact 

 soils but rather on loose humus, sand, and mud soils. CUmatically they 

 are not very sensitive. The rhizome geophytes have the property of 

 maintaining their runners and renewal buds at a certain depth under the 

 surface of the ground; Here belong many of the plants of our deciduous 

 forests, such as Polygonatum, Paris, Anemone nemorosa, and many Carices 

 and Gramineae; also ferns such as Dryopteris and Pteridium. 

 c: Geophyta radicigemmata (root-bud geophytes): a transition group 

 between the eugeophytes and hemicryptophytes. These vascular plants 

 have perennating buds at the base of the stem, below the surface of 



