A gametophyte is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes. Cell division of the zygote results in a new diploid multicellular organism, the second stage in the life cycle known as the sporophyte. The sporophyte can produce haploid spores by meiosis that on germination produce a new generation of gametophytes.
Bryophytes are a group of land plants, sometimes treated as a taxonomic division, that contains three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. In the strict sense, Bryophyta consists of the mosses only. Bryophytes are characteristically limited in size and prefer moist habitats although they can survive in drier environments. The bryophytes consist of about 20,000 plant species. Bryophytes produce enclosed reproductive structures, but they do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of gemmae. Though bryophytes were considered a paraphyletic group in recent years, almost all of the most recent phylogenetic evidence supports the monophyly of this group, as originally classified by Wilhelm Schimper in 1879. The term bryophyte comes from Ancient Greek βρύον (brúon) 'tree moss, liverwort', and φυτόν (phutón) 'plant'.
The embryophytes are a clade of plants, also known as Embryophyta or land plants. They are the most familiar group of photoautotrophs that make up the vegetation on Earth's dry lands and wetlands. Embryophytes have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of freshwater charophyte green algae as a sister taxon of Charophyceae, Coleochaetophyceae and Zygnematophyceae. Embryophytes consist of the bryophytes and the polysporangiophytes. Living embryophytes include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and angiosperms. Embryophytes have diplobiontic life cycles.
The Marchantiophyta are a division of non-vascular land plants commonly referred to as hepatics or liverworts. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information.
Hornworts are a group of non-vascular Embryophytes constituting the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information; the flattened, green plant body of a hornwort is the gametophyte stage of the plant.
Takakia is a genus of two species of mosses known from western North America and central and eastern Asia. The genus is placed as a separate family, order and class among the mosses. It has had a history of uncertain placement, but the discovery of sporophytes clearly of the moss-type firmly supports placement with the mosses.
Dendroceros is a genus of hornworts in the family Dendrocerotaceae. The genus contains about 51 species native to tropical and sub-tropical regions of the world.
Buxbaumia is a genus of twelve species of moss (Bryophyta). It was first named in 1742 by Albrecht von Haller and later brought into modern botanical nomenclature in 1801 by Johann Hedwig to commemorate Johann Christian Buxbaum, a German physician and botanist who discovered the moss in 1712 at the mouth of the Volga River. The moss is microscopic for most of its existence, and plants are noticeable only after they begin to produce their reproductive structures. The asymmetrical spore capsule has a distinctive shape and structure, some features of which appear to be transitional from those in primitive mosses to most modern mosses.
Gossypium tomentosum, commonly known as maʻo, huluhulu or Hawaiian cotton, is a species of cotton plant that is endemic to the Hawaiian Islands. It inhabits low shrublands at elevations from sea level to 120 m (390 ft). Maʻo is a shrub that reaches a height of 1.5–5 ft (0.46–1.52 m) and a diameter of 5–10 ft (1.5–3.0 m). The seed hairs (lint) are short and reddish brown, unsuitable for spinning or twisting into thread.
Environmental sex determination is the establishment of sex by a non-genetic cue, such as nutrient availability, experienced within a discrete period after fertilization. Environmental factors which often influence sex determination during development or sexual maturation include light intensity and photoperiod, temperature, nutrient availability, and pheromones emitted by surrounding plants or animals. This is in contrast to genotypic sex determination, which establishes sex at fertilization by genetic factors such as sex chromosomes. Under true environmental sex determination, once sex is determined, it is fixed and cannot be switched again. Environmental sex determination is different from some forms of sequential hermaphroditism in which the sex is determined flexibly after fertilization throughout the organism’s life.
Hiroshi Inoue was a Japanese botanist specializing in bryology.
Winfrenatia is a genus that contains the oldest-known terrestrial lichen, occurring in fossils preserved in the lower Devonian Rhynie chert. The genus contains the single species Winfrenatia reticulata, named for the texture of its surface. Both the species and the genus were described in 1997.
Eosphagnum inretortum is a species of moss, and the only species of the genus Eosphagnum. Originally described as a species of Sphagnum, it is now a separate genus on the basis of morphological and genetic differences.
Fissidens limbatus commonly known as Herzog's pocket-moss, is a moss in the family Fissidentaceae. This species is found growing in high elevations in tropical America in addition to the US, Mexico and Canada. Montagne first collected F. crispus in 1838.
Raymond Carl Jackson was an American botanist, known as Ray Jackson, noted "for his work in cytogenetics, particularly on polyploidy, and for his discovery of low chromosome numbers in angiosperms."
Wilfred "Wilf" Borden Schofield was a Canadian botanist, specializing in mosses and liverworts. He was considered by many "the foremost bryologist in Canada".
Barbara Ann Whitlock is a botanist, who earned a Ph.D. from Harvard University, with her dissertation Systematics and evolution of chocolate and its relatives c. 2000, an interest which continues.
Polytrichastrum formosum, commonly known as the bank haircap moss, is a species of moss belonging to the family Polytrichaceae.
Xanthoparmelia subramigera is a lichen which belongs to the Xanthoparmelia genus.
Marion Elizabeth Cave was an American plant embryologist and cytogeneticist. She obtained her PhD from University of California, Berkeley where she pioneered the approach to distinguish plant taxonomy using genetics. She continued this work at Berkeley as a research associate. While there, she would be the first person to count the chromosomes in algae, earn her a Guggenheim fellowship in 1952. In addition to her research, she was success at obtaining National Science Foundation funding to create a service that would annually inform how many chromosomes each plant species had to help the field of plant cytology flourish. For her contributions, Volume 33 of Madroño, a genus (Marionella) of Delesseriaceae, and a subgenus (Mscavea) of Echeandia were all dedicated to her.
