372 ECOLOGICAL FACTORS, ETC. 



Heliophobes : 



(i) Pholadophytes. Forms nestling into hollows and avoiding 



much light. 



(2) Skiarophytes. Forms growing under rocks or in their shade. 



Heliophiles : 



(3) Metarrheophytes or attached flexible forms growing in moving 



water. 



(4) Lepyrodophytes or encrusting forms. 



(5) Herpophytes composed of small creeping algae. 



(6) Tranophytes or boring species. 



(7) Cumatophytes or "surf-loving" species. 



(8) Chordophytes, where the thallus has the form of a cord. 



(9) Lithakophytes or lime-encrusted species (Corallinaceae). 



(10) Epiphytes. 



(11) Endophytes. 



Knight and Parke (1931) proposed a brief classification based 

 upon the same criteria, duration and perennation, that Raunkiaer 

 employed for the higher plants. They only distinguished four 

 groups; perennials, pseudoperennials, annuals and casual annuals, 

 and it would require a thorough restudy of many species in order to 

 determine to which group they belong. More recently (1937) 

 Feldmann has proposed a new scheme, based on these same criteria, 

 which can be regarded as the logical elaboration of Knight and 

 Parke's classification: 



(i) ANNUALS 



(a) Species found throughout the year. Spores or oospores germinate immedi- 



ately. 



Ephemerophyceae : Cladophora. 



(b) Species found during one part of the year only. 



(i) Algae present during the rest of the year as a microscopic thallus. 



ECLIPSIOPHYCEAE : {o) with prothallus, Sporochnus. 



(b) with plethysmothallus, Asperococcus. 



(ii) Algae passing the unfavourable season in a resting stage. 

 Hypnophyceae — Resting stage : 



{a) spores, Spongomorpha lanosa. 



(b) oospores, Vaucheria. 



(c) hormogones, Rivularia. 



(d) akinetes, Ulothrix pseudoflacca. 



{e) spores germinate and then become quiescent, 



Diidresnaya. 

 (/) protonema, Porphyra. 



