204 



FORMATIONS AND GUILDS 



[Part I) 



and the lauraceous genus Cassytha — both leafless twiners with haustori: 

 on their stems and more (Ciiscuta) or less (Cassytha) poor in chloro 

 phyll. Others again have the habitat of true epiphjtes ; such are th< 

 mistletoe (Viscum album), Loranthus europaeus and numerous othe 

 Loranthaceae. also several Santalaceae of extra-tropical South America 

 These epiphytic forms are all hemiparasites except Loranthus aphyllus' 



Many are at the sam( 

 time climbers. Finally 

 a separate oecological po 

 sition may be assigned tc 

 those forms that, excep 

 for their organs of repro- 

 duction, are buried withii 

 their host. 



In the case of fungi, stil 

 greater differences in thei 

 mode of life exist ; for cm 

 reason, because they, un 

 like phanerogams, are no' 

 confined to vegetable sub- 

 strata but also attacl 

 animals, and also because 

 man\- species assume dif 

 ferent forms on differen 

 hosts. 



Like saprophytes, para 

 sites belong to a relatively 

 small number of sys 

 tematic groups, and ar 

 most numerous amons 

 fungi and bacteria. Alga- 

 include only a few hole 

 parasites compared witi 

 the more numerous hem! 

 parasites in the grouf 

 Holoparasites and holosa 

 prophytes alike are want 

 ing among mosses, pteridophytes, and gymnosperms. The analog; 

 between the two oecological groups of holop^Crasites and holosaprophyte 

 does not extend to angiosperms. Although there is a parasite (Melampy 

 rum pratense) that apparently can also exist saprophyticallj^ (L. Koch 

 yet the two modes of organic nutrition among angiosperms are systemat 



' According to Johow. 



Fig. 112. Cuscuta europaea. In the centre a willow twig 

 round which the parasite is twining, b reduced leaves, Bl 

 flowers. On the left, connexion of the parasite Ctis with its 

 host W. H baustoria. v, c, s vascular bundle of the host. 

 On the right, seedlings ; t base of seedling dying off. From 

 Strasburger's Te.xt-book of Botany. 



