Laeliinae is a Neotropical subtribe including 40 orchid genera, such as Brassavola and Cattleya. The genus Epidendrum is the largest within this subtribe; this is followed with over 120 species. Genus and Number of Species: Acrorchis Dressler, 1 Adamantinia Van den Berg & M. W. Chase, 1 Alamania La Llave & Lex. 1 Arpophyllum La Llave & Lex, 5 Artorima Dressler & G. E. Pollard, 1 Barkeria Knowles & Westc. 17 Syn. Dothilophis Raf. Brassavola R. Br. 17 Broughtonia R. Br. 6 Syn. Cattleyopsis Lem. Laeliopsis Lindl. Cattleya Lindl. 118 Syn. Maelenia Dum. Sophronitis Lindl. Sophronia Lindl. Lophoglottis Raf. Hoffmannseggella H. G. Jones, Hadrolaelia Chiron & V. P. Castro, Dungsia Chiron & V. P. Castro, Microlaelia Chiron & V. P. Castro, Chironiella Braem, Brasilaelia Campacci, Cattleyella Van den Berg & M. W. Chase, Schluckebieria Braem Caularthron Raf. 3 Syn. Diacrium Benth. Dothilophis Raf. Constantia Barb. Rodr. 5 Dimerandra Schltr. 1 Dinema Lindl. 1 Domingoa Schltr. 5 Syn. Hartwegia Lindl. Nageliella L. O. Williams Encyclia Hook. 120 Epidendrum L. 1500 Syn.
Amblostoma Scheidw. Amblystoma Kuntze, Amphiglottis Salisb. Amphiglottium Lindl. Ex Stein, Auliza Salisb. Auliza Salisb. Ex Small, Aulizeum Lindl. Ex Stein, Coilostylis Raf. Didothion Raf. Diothonea Lindl. Epidanthus L. O. Williams, Epidendropsis Garay & Dunst. Gastropodium Lindl. Hemiscleria Lindl. Kalopternix Garay & Dunst. Lanium Benth. Larnandra Raf. Minicolumna Brieger, Nanodes Lindl. Neohlemannia Kraenzl. Neowilliamsia Garay, Nyctosma Raf. Oerstedella Rchb.f. Physinga Lindl. Pleuranthium Benth. Pseudepidendrum Rchb.f. Psilanthemum Klotszch ex Stein, Seraphyta Fisch. & C. A. Mey. Spathiger Small, Spathium Lindl. Ex Stein, Stenoglossum Kunth, Tritelandra Raf. Guarianthe Dressler & W. E. Higgins, 4 Hagsatera R. González, 2 Homalopetalum Rolfe, 7 Syn. Pinelia Lindl. Pinelianthe Rauschert Isabelia Barb. Rodr. 3 Syn. Neolauchea Kraenzl. Sophronitella Schltr. Jacquiniella Schltr. 11 Syn. Dressleriella Brieger, Briegeria Senghas Laelia Lindl. 25 Syn. Amalia Lindl. Amalias Hofmsgg. Schomburgkia Lindl. Laeliocatarthron Leptotes Lindl. 5 Loefgrenianthus Hoehne, 1 Meiracyllium Rchb.f.
2 Microepidendrum Brieger ex W. E. Higgins, 1 Myrmecophila Rolfe, 10 Nidema Britton & Millsp. 2 Oestlundia W. E. Higgins, 4 Orleanesia Barb. Rodr. 11 Prosthechea Knowles & Westc. 100 Syn. Epithecium Knowles & Westc. Hormidium Heynh. Anacheilium Hoffmgg. Euchile Withner, Pseudencyclia Chiron & V. P. Castro. Panarica Withner & P. A. Harding, Pollardia Withner & P. A. Harding Pseudolaelia Porto & Brade, 10 Syn. Renata Ruschi Psychilis Raf. 15 Pygmaeorchis Brade, 2 Quisqueya Dod, 4 Rhyncholaelia Schltr, 2 Scaphyglottis Poepp. & Endl. 60 Syn. Hexisea Lindl. Cladobium Lindl. Hexadesmia Brongn. Tetragamestus Rchb.f. Reichenbachanthus Barb. Rodr. Fractiungis Schltr. Leaoa Schltr. & Porto, Pachystele Schltr. Costaricaea Schltr. Ramonia Schltr. Platyglottis L. O. Williams Tetramicra Lindl. 13 van den Berg, C. W. E. Higgins, R. L. Dressler, W. M. Whitten, M. A. Soto Arenas, A. Culham and M. W. Chase. 2000. A Phylogenetic Analysis of Laeliinae Based on Sequence Data from Internal Transcribed Spacers of Nuclear Ribosomal DNA. Lindleyana 15: 96–114.
Van den Berg, C. et al. 2005. Subtribe Laeliinae. Pp. 181–316 In Pridgeon, A. M. Cribb, P. J. Chase, M. W. Rasmussen, F. N. Genera Orchidacearum Vol. IV. Oxford University Press, Oxford. Van den Berg C, Chase M. W. 2005 Nomenclatural notes on Laeliinae - IV. New combinations in Sophronitis. Kew Bull. 59.: 565-567 van den Berg, C. 2014. Reaching a compromise between conflicting nuclear and plastid phylogenetic trees: a new classification for the genus Cattleya. Phytotaxa 186: 075–086. Photo album of Laeliinae species and hybrids Checklist of Laeliinae genera
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
Plants are multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Plants were treated as one of two kingdoms including all living things that were not animals, all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants and other gymnosperms and their allies, liverworts and the green algae, but excludes the red and brown algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria, their chloroplasts contain b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is common.
There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants. Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecosystems on land. Plants that produce grain and vegetables form humankind's basic foods, have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs; the scientific study of plants is known as a branch of biology. All living things were traditionally placed into one of two groups and animals; this classification may date from Aristotle, who made the distincton between plants, which do not move, animals, which are mobile to catch their food. Much when Linnaeus created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia and Animalia. Since it has become clear that the plant kingdom as defined included several unrelated groups, the fungi and several groups of algae were removed to new kingdoms.
However, these organisms are still considered plants in popular contexts. The term "plant" implies the possession of the following traits multicellularity, possession of cell walls containing cellulose and the ability to carry out photosynthesis with primary chloroplasts; when the name Plantae or plant is applied to a specific group of organisms or taxon, it refers to one of four concepts. From least to most inclusive, these four groupings are: Another way of looking at the relationships between the different groups that have been called "plants" is through a cladogram, which shows their evolutionary relationships; these are not yet settled, but one accepted relationship between the three groups described above is shown below. Those which have been called "plants" are in bold; the way in which the groups of green algae are combined and named varies between authors. Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom.
The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the green algae, red algae and brown algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, they are no longer classified as plants as defined here; the Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions, the green plants have the following features in common, they undergo closed mitosis without centrioles, have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria. Two additional groups, the Rhodophyta and Glaucophyta have primary chloroplasts that appear to be derived directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in the pigments which are used in photosynthesis and so are different in colour.
These groups differ from green plants in that the storage polysaccharide is floridean starch and is stored in the cytoplasm rather than in the plastids. They appear to have had a common origin with Viridiplantae and the three groups form the clade Archaeplastida, whose name implies that their chloroplasts were derived from a single ancient endosymbiotic event; this is the broadest modern definition of the term'plant'. In contrast, most other algae not only have different pigments but have chloroplasts with three or four surrounding membranes, they are not close relatives of the Archaeplastida having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in the broadest modern definition of the plant kingdom, although they were in the past; the green plants or Viridiplantae were traditionally divided into the green algae (including
In plant systematics Epidendroideae is a subfamily of the orchid family, Orchidaceae. Epidendroideae is larger than all the other orchid subfamilies together, comprising more than 15,000 species in 576 genera. Most Epidendroid orchids are tropical epiphytes with pseudobulbs. There are, some terrestrials such as Epipactis and a few myco-heterotrophs, which are parasitic upon mycorrhizal fungi, they contain the remaining orchids with a single, fertile anther, fully incumbent to suberect. The anther form arises from early anther bending; the incumbent anther is pointed backward in many genera. Most have hard pollinia, i.e. a mass of waxy pollen or of coherent pollen grains. The pollinia are without; the stigma are three-lobed. The apical part of the middle stigma lobe forms a stipe; the ovary is unilocular. The leaves are distichous or spiraling; the Epidendroideae are difficult to classify. They have been divided in “lower epidendroids” and “higher epidendroids”. Epiphytes are plants which grow on top of other plants.
They are not parasitic. By growing on other plants, the epiphytes can reach to the light better or where they can avoid struggling for light. Many mosses and lichens are epiphytes, as are 10 per cent of all seed plants and ferns. Epiphytes are common in some groups of plants, such as ferns, mosses and algae. Over half of the 20,000 species of orchids are epiphytes. Most epiphytic seed plants and ferns are found in tropical and subtropical rainforests because they need high humidity to survive; the areas which most epiphytes grow are the montane rainforests. Epiphytic orchids are found on many positions of the host tree, depending on species requirements and size, some large species will grow in a fork, whereas some small species scramble through thin branches, other species will climb up the trunk etc. etc. The trees provide many habitats with different conditions of temperature and light. In temperate places, epiphytes are most common in moist forests, such as the rainforests in Queensland. Epiphytes are not adapted to droughts in the same way are other flora, because they don’t have access to the ground, but they still have some mechanisms to help them survive.
Some become dormant for months at a time. They contain absorptive plants that are capable at taking up water when it is available and preventing drought when water is scarcer. CAM can be impeded by higher night-time temperatures, dehydrated tissues, high saturation deficits in the surrounding air, which lower the "stomata conductance" of the epiphytes, reducing the CO2 uptake, which in turn reduces growth and reproduction and induces carbon loss. Higher temperatures, strain on evaporation, contact to light cause CAM-idling, the epiphyte closing its stomata when it becomes stressed, that brings down the range of habitats a species can inhabit. Epiphyte species work biomasses are much more sensitive to different relative moisture levels than other plants; the Epidendroideae subfamily is divided into two clades or subgroups known as the higher epidendroids and the lower epidendroids. The higher epidendroids are monophyletic and polyphyletic; the tribes are listed below: This classification has a rather ephemeral nature and is prone to frequent revision.
Changes are to occur as new morphological and genetic data become available. A phylogenetic analysis of the Orchidaceae - evidence from rbcL nucleotide sequences Orchid Tree: a phylogeny of epiphytes on the tree of life
Laelia is a small genus of 25 species in the orchid family. Laelia species are found in areas of subtropical or temperate climate in Central and South America, but in Mexico. Laelia is abbreviated L. in the horticultural trade. Epiphyte herbs with laterally compressed pseudobulbs. One to four leathery or fleshy leaves are born near the top of each pseudobulb, can be broadly ovate to oblong; the inflorescence is a terminal raceme. The flowers have 8 pollinia. Species of Laelia can be found from western Mexico south to Bolivia, from sea level to mountain forests; the genus Laelia was described as part of subfamily Epidendroideae by John Lindley. Brazilian Laelias, after being classified for several years under Sophronitis, have now been placed in the genus Cattleya. Moreover, species placed in the genus Schomburgkia have been moved either to the genus Laelia or Myrmecophila. Laelia comprises the following species: Species in this genus are found in forests from sea level to mountain habitats above 2000 m.
Species from above 2000 m of elevation like L. albida, L. autumnalis are adapted to temperate climates and can be grown outdoors in places like the Mexican Plateau and other subtropical areas with cool summers. Laelia is one of the orchid genera known to use crassulacean acid metabolism photosynthesis, which reduces evapotranspiration during daylight because carbon dioxide is collected at night. Laelias can be grown fastened to tree trunks, as long; the growing medium must have good drainage drying after watering. If grown mounted they need 50-70% humidity, while cooler temperatures increase the blooming process. Watering can be with lower frequency in winter. Fertilization can be done with a dilute solution, twice a month during growing season. Media related to Laelia at Wikimedia Commons
The Orchidaceae are a diverse and widespread family of flowering plants, with blooms that are colourful and fragrant known as the orchid family. Along with the Asteraceae, they are one of the two largest families of flowering plants; the Orchidaceae have about 28,000 accepted species, distributed in about 763 genera. The determination of which family is larger is still under debate, because verified data on the members of such enormous families are continually in flux. Regardless, the number of orchid species nearly equals the number of bony fishes and is more than twice the number of bird species, about four times the number of mammal species; the family encompasses about 6–11% of all seed plants. The largest genera are Bulbophyllum, Epidendrum and Pleurothallis, it includes Vanilla–the genus of the vanilla plant, the type genus Orchis, many cultivated plants such as Phalaenopsis and Cattleya. Moreover, since the introduction of tropical species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids and cultivars.
Orchids are distinguished from other plants, as they share some evident, shared derived characteristics, or synapomorphies. Among these are: bilateral symmetry of the flower, many resupinate flowers, a nearly always modified petal, fused stamens and carpels, small seeds. All orchids are perennial herbs, they can grow according to two patterns: Monopodial: The stem grows from a single bud, leaves are added from the apex each year and the stem grows longer accordingly. The stem of orchids with a monopodial growth can reach several metres in length, as in Vanda and Vanilla. Sympodial: Sympodial orchids have a front and a back; the plant produces a series of adjacent shoots, which grow to a certain size and stop growing and are replaced. Sympodial orchids grow laterally following the surface of their support; the growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. While a new lead is developing, the rhizome may start its growth again from a so-called'eye', an undeveloped bud, thereby branching.
Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil. Terrestrial orchids may form corms or tubers; the root caps of terrestrial orchids are white. Some sympodial terrestrial orchids, such as Orchis and Ophrys, have two subterranean tuberous roots. One is used as a food reserve for wintry periods, provides for the development of the other one, from which visible growth develops. In warm and humid climates, many terrestrial orchids do not need pseudobulbs. Epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis, called velamen, has the function of absorbing humidity, it can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes; the cells of the root epidermis grow at a right angle to the axis of the root to allow them to get a firm grasp on their support.
Nutrients for epiphytic orchids come from mineral dust, organic detritus, animal droppings and other substances collecting among on their supporting surfaces. The base of the stem of sympodial epiphytes, or in some species the entire stem, may be thickened to form a pseudobulb that contains nutrients and water for drier periods; the pseudobulb has a smooth surface with lengthwise grooves, can have different shapes conical or oblong. Its size is variable; some Dendrobium species have long, canelike pseudobulbs with short, rounded leaves over the whole length. With ageing, the pseudobulb becomes dormant. At this stage, it is called a backbulb. Backbulbs still hold nutrition for the plant, but a pseudobulb takes over, exploiting the last reserves accumulated in the backbulb, which dies off, too. A pseudobulb lives for about five years. Orchids without noticeable pseudobulbs are said to have growths, an individual component of a sympodial plant. Like most monocots, orchids have simple leaves with parallel veins, although some Vanilloideae have reticulate venation.
Leaves may be ovate, lanceolate, or orbiculate, variable in size on the individual plant. Their characteristics are diagnostic, they are alternate on the stem folded lengthwise along the centre, have no stipules. Orchid leaves have siliceous bodies called stegmata in the vascular bundle sheaths and are fibrous; the structure of the leaves corresponds to the specific habitat of the plant. Species that bask in sunlight, or grow on sites which can be very dry, have thick, leathery leaves and the laminae are covered by a waxy cuticle to retain their necessary water supply. Shade-loving species, on the other hand, have thin leaves; the leaves of most orchids are perennial, that is, they live for several years, while others those with plicate leaves as in Catasetum, shed them annually and de
Asparagales is an order of plants in modern classification systems such as the Angiosperm Phylogeny Group and the Angiosperm Phylogeny Web. The order takes its name from the type family Asparagaceae and is placed in the monocots amongst the lilioid monocots; the order has only been recognized in classification systems. It was first put forward by Huber in 1977 and taken up in the Dahlgren system of 1985 and the APG in 1998, 2003 and 2009. Before this, many of its families were assigned to the old order Liliales, a large order containing all monocots with colourful tepals and lacking starch in their endosperm. DNA sequence analysis indicated that many of the taxa included in Liliales should be redistributed over three orders, Liliales and Dioscoreales; the boundaries of the Asparagales and of its families have undergone a series of changes in recent years. In the APG circumscription, Asparagales is the largest order of monocots with 14 families, 1,122 genera, about 36,000 species; the order is circumscribed on the basis of molecular phylogenetics, but is difficult to define morphologically, since its members are structurally diverse.
Most species of Asparagales are herbaceous perennials, although some are climbers and some are tree-like. The order contains many geophytes. According to telomere sequence, at least two evolutionary switch-points happened within the order. Basal sequence is formed by TTTAGGG like in majority of higher plants. Basal motif was changed to vertebrate-like TTAGGG and the most divergent motif CTCGGTTATGGG appears in Allium. One of the defining characteristics of the order is the presence of phytomelanin, a black pigment present in the seed coat, creating a dark crust. Phytomelanin is found in most families of the Asparagales; the leaves of all species form a tight rosette, either at the base of the plant or at the end of the stem, but along the stem. The flowers are not distinctive, being'lily type', with six tepals and up to six stamina; the order is thought to have first diverged from other related monocots some 120–130 million years ago, although given the difficulty in classifying the families involved, estimates are to be uncertain.
From an economic point of view, the order Asparagales is second in importance within the monocots to the order Poales. Species are used as food and flavourings, as cut flowers, as garden ornamentals. Although most species in the order are herbaceous, some no more than 15 cm high, there are a number of climbers, as well as several genera forming trees, which can exceed 10 m in height. Succulent genera occur in several families. All species have a tight cluster of leaves, either at the base of the plant or at the end of a more-or-less woody stem as with Yucca. In some cases the leaves are produced along the stem; the flowers are in the main not distinctive, being of a general'lily type', with six tepals, either free or fused from the base and up to six stamina. They are clustered at the end of the plant stem; the Asparagales are distinguished from the Liliales by the lack of markings on the tepals, the presence of septal nectaries in the ovaries, rather than the bases of the tepals or stamen filaments, the presence of secondary growth.
They are geophytes, but with linear leaves, a lack of fine reticular venation. The seeds characteristically have the external epidermis either obliterated, or if present, have a layer of black carbonaceous phytomelanin in species with dry fruits; the inner part of the seed coat is collapsed, in contrast to Liliales whose seeds have a well developed outer epidermis, lack phytomelanin, display a cellular inner layer. The orders which have been separated from the old Liliales are difficult to characterize. No single morphological character appears to be diagnostic of the order Asparagales; the flowers of Asparagales are of a general type among the lilioid monocots. Compared to Liliales, they have plain tepals without markings in the form of dots. If nectaries are present, they are in the septa of the ovaries rather than at the base of the tepals or stamens; those species which have large dry seeds have a dark, crust-like outer layer containing the pigment phytomelan. However, some species with hairy seeds, berries, or reduced seeds lack this dark pigment in their seed coats.
Phytomelan is not unique to Asparagales but it is common within the order and rare outside it. The inner portion of the seed coat is completely collapsed. In contrast, the morphologically similar seeds of Liliales have no phytomelan, retain a cellular structure in the inner portion of the seed coat. Most monocots are unable to thicken their stems once they have formed, since they lack the cylindrical meristem present in other angiosperm groups. Asparagales have a method of secondary thickening, otherwise only found inDioscorea. In a process called'anomalous secondary growth', they are able to create new