Phaeoceros laevis
Encyclopedia
Phaeoceros laevis is a species of hornwort
of the genus Phaeoceros
. It is commonly found in areas where moisture is plentiful, such as moist soils in fields, the banks of streams and rivers or inundated beneath the surface of the rivers. It grows to a maximum height of about 5 millimetres and the plants are monoecious; the sex organs are visible on the dorsal surface.
The thallus is nearly flat on the upper surface. It is of dark green and somewhat lustrous color, devoid of intercellular spaces. Its capsule is commonly 6 inch to 18 inch in length. The base is surrounded by a cylindrical sheath that often flares at the mouth. Spores are yellow with a granular-papillose surface. The elaters are yellowish, often branches, and varying in size and form. The slender green capsules, when produced in large numbers, resemble grass tufts. Mature spores are necessary for species determination.
The cytology
of P. laevis has been subject to considerable study. In 1909, Lotsy reported that the plant contained one chloroplast in each cell of the gametophyte
and two in each cell of the sporophyte
. The sporophyte is likened to an elongated spindle. Research conducted by Lorbeer in 1924 revealed that two plastids are present in a cell when it is undergoing cell division, of which according to McAllister
may vary in size. The centrosomes of the species, much like Marchantia polymorpha
, are composed of two centrioles apposed end-to end, which are connected by a continuation of their cartwheel structures.
Hornwort
Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant.Hornworts may be found worldwide,...
of the genus Phaeoceros
Phaeoceros
Phaeoceros is a genus of hornworts in the family Notothyladaceae. The genus is global in its distribution. Its name means 'yellow horn', and refers to the characteristic yellow spores that the plants produce in the horn-shaped sporophyte. The genus Phaeoceros was first recognized in 1951 by...
. It is commonly found in areas where moisture is plentiful, such as moist soils in fields, the banks of streams and rivers or inundated beneath the surface of the rivers. It grows to a maximum height of about 5 millimetres and the plants are monoecious; the sex organs are visible on the dorsal surface.
The thallus is nearly flat on the upper surface. It is of dark green and somewhat lustrous color, devoid of intercellular spaces. Its capsule is commonly 6 inch to 18 inch in length. The base is surrounded by a cylindrical sheath that often flares at the mouth. Spores are yellow with a granular-papillose surface. The elaters are yellowish, often branches, and varying in size and form. The slender green capsules, when produced in large numbers, resemble grass tufts. Mature spores are necessary for species determination.
The cytology
Cell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...
of P. laevis has been subject to considerable study. In 1909, Lotsy reported that the plant contained one chloroplast in each cell of the gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
and two in each cell of the sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
. The sporophyte is likened to an elongated spindle. Research conducted by Lorbeer in 1924 revealed that two plastids are present in a cell when it is undergoing cell division, of which according to McAllister
McAllister
-People surnamed McAllister:*Colin McAllister Scottish interior designer*Craig McAllister Scottish footballer*David McAllister German politician*Deuce McAllister American football player....
may vary in size. The centrosomes of the species, much like Marchantia polymorpha
Marchantia polymorpha
Marchantia polymorpha, sometimes known as the common liverwort or umbrella liverwort, is a large liverwort with a wide distribution around the world. It is variable in appearance and has several subspecies. It is dioecious, having separate male and female plants.-Description:It is a thallose...
, are composed of two centrioles apposed end-to end, which are connected by a continuation of their cartwheel structures.