Hildenbrandiales is an order of crustose forms red alga which bear conceptacles[2] and produce secondary pit-connections.[3] They reproduce by vegetative gemmae[4] as well as tetrasporangia, which are produced inside the conceptacles. The way in which the tetraspores are produced is unusual enough to justify the formation of this distinct order.[2] Some members of the order are known from freshwater rivers as well.[5]

Hildenbrandiales
Hildenbrandia rivularis
Scientific classification Edit this classification
(unranked): Archaeplastida
Division: Rhodophyta
Class: Florideophyceae
Subclass: Hildenbrandiophycidae
G.W.Saunders & Hommersand
Order: Hildenbrandiales
Pueschel & Cole, 1982
Family: Hildenbrandiaceae
Rabenhorst, 1868
Genera[1]

Systematics edit

Hildenbradiales are difficult to discriminate on morphological grounds; tetrasporangia morphology is the only vaguely reliable character, but molecular techniques have indicated a monophyletic Apophlaea within a paraphyletic Hildenbrandia, with many Hildenbrandia species being recognized as non-monophyletic.[1]

References edit

  1. ^ a b Sherwood, A. R.; Sheath, R. G. (2003). "Systematics of the Hildenbrandiales (Rhodophyta): Gene Sequence and Morphometric Analyses of Global Collections". Journal of Phycology. 39 (2): 409–422. doi:10.1046/j.1529-8817.2003.01050.x.
  2. ^ a b Pueschel, C. (1982). "Ultrastructural observations of tetrasporangia and conceptacles in Hildenbrandia (Rhodophyta: Hildenbrandiales)". European Journal of Phycology. 17 (3): 333–341. doi:10.1080/00071618200650331.
  3. ^ Pueschel, C. (1988). "Secondary pit connections in Hildenbrandia (Rhodophyta, Hildenbrandiales)". European Journal of Phycology. 23: 25–51. doi:10.1080/00071618800650031.
  4. ^ Sherwood, A. R.; Sheath, R. G. (2000). "Microscopic analysis and seasonality of gemma production in the freshwater red alga Hildenbrandia angolensis (Hildenbrandiales, Rhodophyta)". Phycological Research. 48 (4): 241. doi:10.1111/j.1440-1835.2000.tb00220.x.
  5. ^ Khan, M. (1974). "On a fresh water Hildenbrandia Nardo. From India". Hydrobiologia. 44 (2–3): 237–240. doi:10.1007/BF00187272.