Petalophyllum | |
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Scientific classification | |
Kingdom: | Plantae |
Division: | Marchantiophyta |
Class: | Jungermanniopsida |
Order: | Fossombroniales |
Family: | Petalophyllaceae |
Genus: | Petalophyllum Nees & Gottsche ex Lehmann |
Species | |
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Petalophyllum, or petalwort, [1] is a genus of liverworts in the order Fossombroniales. [2]
The plants are small, reaching lengths of up to about 15 mm (0.6 in), and thallose; that is, the plant is not differentiated into root, stem, and leaf. The thallus consists of a midrib flanked by two wings that bear leaf-like lamellae on their dorsal surface. The ventral surface bears rhizoids and two rows of small scales. [3]
Petalophyllum is dioicous. The gametangia are individually subtended by extensions of the dorsal lamellae. Antheridia occur in rows or clusters near the apex of the thallus. Archegonia are clustered and surrounded by a pesudoperianth. Asexual reproduction occurs via apical tubers. [3]
Petalophyllum lives primarily in seasonally dry habitats on disturbed soils and sand dunes in North America, western Europe, northern Africa, India, New Zealand, and Western Australia. There are currently five recognized species: [3] [4]
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.
Metzgeriales is an order of liverworts. The group is sometimes called the simple thalloid liverworts: "thalloid" because the members lack structures resembling stems or leaves, and "simple" because their tissues are thin and relatively undifferentiated. All species in the order have a small gametophyte stage and a smaller, relatively short-lived, spore-bearing stage. Although these plants are almost entirely restricted to regions with high humidity or readily available moisture, the group as a whole is widely distributed, and occurs on every continent except Antarctica.
Jungermanniopsida is the largest of three classes within the division Marchantiophyta (liverworts).
Monoicy is a sexual system in haploid plants where both sperm and eggs are produced on the same gametophyte, in contrast with dioicy, where each gametophyte produces only sperm or eggs but never both. Both monoicous and dioicous gametophytes produce gametes in gametangia by mitosis rather than meiosis, so that sperm and eggs are genetically identical with their parent gametophyte.
Bryology is the branch of botany concerned with the scientific study of bryophytes. Bryologists are people who have an active interest in observing, recording, classifying or researching bryophytes. The field is often studied along with lichenology due to the similar appearance and ecological niche of the two organisms, even though bryophytes and lichens are not classified in the same kingdom.
Cavicularia densa is the only species in the liverwort genus Cavicularia. The species was first described in 1897 by Franz Stephani, and is endemic to Japan, where it grows on fine moist soil.
Kymatocalyx rhizomaticus is a species of liverwort in the Cephaloziellaceae family. It is endemic to Malaysia. It was previously known as Stenorrhipis rhizomatica.
Haplomitriopsida is a newly recognized class of liverworts comprising fifteen species in three genera. Recent cladistic analyses of nuclear, mitochondrial, and plastid gene sequences place this monophyletic group as the basal sister group to all other liverworts. The group thus provides a unique insight into the early evolution of liverworts in particular and of land plants in general.
Blasiales is an order of liverworts with a single living family and two species. The order has traditionally been classified among the Metzgeriales, but molecular cladistics suggests a placement at the base of the Marchantiopsida.
Aneura mirabilis is a parasitic species of liverworts in the family Aneuraceae. It was first described in 1933, as Cryptothallus mirabilis. Plants of this species are white as a result of lacking chlorophyll, and their plastids do not differentiate into chloroplasts.
Cryptothallus is a previously recognized genus of liverworts in the family Aneuraceae. The plants are small, and are white to pale green as a result of lacking chlorophyll. This feature led to the creation of a separate genus. The morphology of species assigned to Cryptothallus is very similar to that of Aneura. As a result, Karen Renzaglia in 1982 suggested that the only species then placed in the genus, Cryptothallus mirabilis, may be considered "merely as an achlorophyllous species of Aneura." Wickett and Goffinet argued the same position on the basis of sequences of nuclear, mitochondrial, and plastid DNA, and moved Cryptothallus mirabilis to Aneura. A 2010 molecular phylogenetic study confirmed the position of Cryptothallus within Aneura. This was accepted in the 2016 world checklist of hornworts and liverworts.
Solenostomataceae is a family of liverworts in the order Jungermanniales.
Petalophyllaceae is a family of liverworts in the order Fossombroniales. Most species are thallose; that is, the plant is not differentiated into root, stem, and leaf. The thallus is typically small and bears lamellae on its dorsal surface that give it a ruffled, leafy appearance.
Phymatoceros is the only genus in the hornwort family Phymatocerotaceae and order Phymatocerotales. It includes only two species.
Acrobolbus epiphytus is a liverwort species in the genus Acrobolbus. It occurs in New Zealand.
Petalophyllum ralfsii, the petalwort, is a liverwort of the order Fossombroniales. It is a small green bryophyte that occurs in the Mediterranean region as far east as Turkey, and along the Atlantic coast of Europe as far as northwest Scotland. It grows primarily on moist sand dunes.
Cephaloziaceae is a family of liverworts.
Petalophyllum americanum, common name petalwort, is a species of liverwort in the order Fossombroniales. It is endemic to the Gulf Coast of the United States in Arkansas, Louisiana, Mississippi, and Texas. It was first described as the European species Petalophyllum ralfsii in 1919, but a detailed study later showed that the North American form is a distinct species.
Tylimanthus pseudosaccatus is a bryophyte, a species from the liverwort family Acrobolbaceae. The family grows on logs, rocks, and soil. Under certain circumstances, however, they are epiphyte, growing on other plant species.
Monoclea forsteri is one of the two species in the thallose liverwort family Monocleaceae. It is dioicous with the capsule dehiscing with a single longitudinal slit. Endemic and widely distributed throughout New Zealand, it is also the country's largest thalloid liverwort. Hooker described the species in 1820. The holotype is in the British Museum.
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