摘要:

ABSTRACTA Pikeaspecies attributed toPikea californicaHarvey has been established in England since at least 1967. Previously, this species was believed to occur only in Japan and Pacific North America. Comparative morphological studies on field‐collected material and cultured isolates from England, California, and Japan and analysis of organellar DNA restriction fragment length polymorphisms, detected using labeled organellar DNA as a non‐radioactive probe, showed that EnglishPikeais conspecific withP. californicafrom California. Both populations consist of dioecious gametophytes with heteromorphic life histories involving crustose tetrasporophytes; 96% of organellar DNA bands were shared between interoceanic samples. A second dioecious species ofPikea, P. pinnataSetchell in Collins, Holden et Setchell, grows sympatrically withP. californicanear San Francisco but can be distinguished by softer texture, more regular branching pattern, and elongate cystocarpic axes.Pikea pinnataandP. californicasamples shared 49–50% of organellar DNA bands, consistent with their being distinct species. Herbarium specimens ofP. robustaAbbott resembleP. pinnatain some morphological features but axes are much wider;P. robustamay represent a further, strictly sub‐tidal species but fertile material is unknown.Pikeathalli from Japan, previously attributed toP. californicaand described here asPikea yoshizakiisp. nov., are monoecious and show a strikingly different type of life history. After fertilization, gonimoblast filaments grow outward through the cortex and form tetrasporangial nemathecia; released tetraspores develop directly into erect thalli. Tetrasporoblastic life histories are characteristic of certain members of the Phyllophoraceae but were previously unknown in the Dumontiaceae. JapaneseP. yoshizakiishared 55 and 56% of organellar DNA bands withP. californicaandP. pinnata, respectively; phylogenetic analysis indicated equally distant relationships to both species.Pikea yoshizakiior a closely similar species with the same life history occurs in southern California and

ISSN:0022-3646    

DOI:10.1111/j.0022-3646.1996.00176.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY