Magnoliaceae

Magnoliaceae, the magnoliaceae, or magnolias are a family of Angiosperms belonging to the order Magnoliales. The total number of genera is disputed. 17 are accepted, others accept only two: Magnolia and Liriodendron, with about 225 species, which are distributed throughout tropical and temperate Asia and boreal and southern America.

Distribution and habitat

Magnoliaceae are a family of trees and shrubs that are widely distributed in temperate and tropical parts of southeast Asia, and in tropical Central and South America, and in North America. In the Neotropics, about 45 species of magnoliaceae are known (Lozano 1994), distributed in Central America, the Antilles, the Biogeographical Chocó, eastern Guianas, the Andes, the Andean-Amazonian slope, and southeastern Brazil. The greatest diversity of magnoliaceae in the Neotropics is found in Colombia, with 33 species (including two possible new species), all of the genus Magnolia. Of the Colombian species, 29 are exclusive to the country, and are located mainly in humid and very humid forests, from sea level to 3000 m s. no. m., in the Andean and sub-Andean strip, and in the Chocó Biogeográfico (Lozano 1983,1994,Velásquez & Serna 2005)

Description

Magnoliaceae are trees that are easy to recognize by their monopodous stems and dense foliage. In addition, on the ground where they grow, it is common to find a mantle formed by its dry leaves of leathery consistency and glossy upper part (which is why several of these species are known as leaf litter; this mantle is accompanied by foliar and floral bracts, sepals, and petals fleshy, and remains of thick-walled fruits and woody receptacles.

The less disturbed populations of magnoliaceae have a gregarious distribution and, on some occasions, can even form dense stands, with large emerging adult trees and numerous seedlings. An example of this are some populations of Magnolia yarumalenis located on the Western Cordillera in southwestern Antioquia. In general, the populations that grow in fragmented and isolated habitats are composed only of occasional adult trees, located on the periphery of the fragments and with little natural generation.

The pollination of these plants is generally carried out by coleoptera (beetles), while the dispersal of their seeds is frequently carried out by birds or mammals. The isolation of deteriorated populations hinders the dynamics of these processes as the gene flow between them decreases, which can lead to local extinction.

Cultivate ornamental magnolio in flower.

• Trees or shrubs, glabros or with simple hairs, monopoly or sympathetic growth.
• Simple leaves, medium to large, whole or 2-10-lobed, in spiral, pinnatinervia, persistent or caducas, with large, free or partly adnatas to the peciolo, in principle surrounding and protecting the terminal yolk, later caducas and leaving a ring scar on the knot. Stomas only in foliar, paracytic, seldom anocytic.
• Talles with nodes with 6 or more lagoons, with wide radios, stratified secondary floem.
• Terminal bisexual flowers or pseudoaxillary on a brachyblasto axilar, perfect, seldom unisexual, peduncle with one or more deciduous spataceae that leave anular scars. Spiral periant or spirocyclic (3-4 tender verticils), uniform not differentiated in chalice and corollary, 6-18 deciduous, free, imbricated tepalos. Receptacle lengthened. 50-200 stamens, free, spirals, short or long filaments, adnata antennas, linears, 2-loculars, tetrasporangiadas, introrse dehiscence, latrorsa or seldom extrorsa, usually prolonged connective; carpals (1-)20-200, apocárpicos or sincárpicos, spirals, juic
• Apocárpic or syncárpic fruit, the carpals are opened by the dorsal or ventral suture, rarely circumcised or indehiscent, or a loccusted capsule; usually hardened, woody, sometimes fleshy, low.
• Seeds 1 or more per carpel, large, in the dehiscent carpals usually pendants of the elongated funicule, in the indehiscents the ariloid testa adherent to the endocarp, abundant endosperm, oily, non ruminated, embryo often.
• Polen reniforme a navicular, with a distal colpo, seldom tricotomosulcado, ectexina differentiated in tectum, columelas and basal layer, perforated and rough tectum, fine endexine, lamelada or well absent, intina thicker than the exine, in lamelated layers.
• chromosomal number: x = 19; small chromosomes; frequent polyployment in temperate or Himalaya species.

Ecology

Protogynous flowers, pollinated by beetles that feed on the stigmas, pollen, nectar, and secretions from the petals. In species with dehiscent fruits, the seeds hang for some time from the elongated funicles until they fall; in those with indehiscent fruits, the resulting syncarp falls as a unit. In Liriodendron the samaroid carpels are dispersed by the wind. Species typical of temperate forests and tropical forests of medium and high altitude (up to 3500 m), rarely at low altitude. The current fragmented distribution is the result of forced migration events and area shrinkage due to the brutal climate changes during the Pleistocene. Physiologically, they are C₃ plants.

Phytochemistry

In magnoliaceae, antioxidant structures such as magnodiol and honokiol have been found, which are potentially antioxidant compounds for pharmaceutical and food use. In addition, other chemical structures with antimalarial, antiplatelet, antiinflammatory, and cytotoxic activities have been found.

Other substances such as essential oils present in large idioblasts. Sesquiterpene lactones (of the germanacrolide, eudesmanolide, elemanolide and guainolide type), flavonols, procyanidins, caffeic acid, cyclitols, lignans, neolignans and alkaloids present, as well as tyrosine-derived cyanogenetic compounds (taxifolin and triglokinin) in Liriodendron tulipifera and Magnolia sprengeri. Gallitannins and ellagitannins absent. Leaves frequently very silicified.

Uses

Most magnolia species have historically been used as lumber for home construction and as roundwood for carpentry, cabinetry, beams, and flooring. The exploitation occurs mainly at the local level, and in the market its wood is known by names such as almanegra or hojarasco. Magnolia hernandezii is also used to make “grinders” that are used as kitchen utensils. Magnolia officinalis, M. champaca and other species produce substances used in traditional and modern pharmacopoeia. Other species are used in gardens for their ornamental properties, having obtained numerous hybrid cultivars.

Taxonomy

The Magnoliaceae, since their description, have been considered as a primitive group of Angiosperms, around which one or other families have been placed, depending on the system, to create an Order Magnoliales. The APW (Angiosperm Phylogeny Website) considers it to be the sister group of the apical clade of the Order, consisting of (Degeneriaceae, Himantandraceae) (Eupomatiaceae, Annonaceae).

Generic taxa

Magnolia hodgsonii

The internal systematics of the family are highly controversial, ranging from 12 genera (eg Hutchinson, 1964) to 7 (Nooteboom, 1993) or only 2 (see APW above). Recent molecular phylogeny studies leave Liriodendron as a genus undisputed in its validity, but the rest arise as internal branches of a strongly paraphyletic Magnolia genus, so the trend current is to include Manglietia, Pachylarnax, Kmeria, Elmerrillia and Michelia in a broad genus Magnolia, an option we follow here. The only candidate taxon to possibly maintain its generic status would be Talauma, as it is the basal branch of the phylogenetic tree of the genus Magnolia, but this option needs a consensus that has not yet been reached. achieved among botanists.

The two genera recognized here can be distinguished as follows:

Flower and leaves Liriodendron tulipifera

• Leaves 2-10-lobed, truncated apex or widely chosen. Exort antennas. Samoid carpals in fruit, caducos:

Liriodendron L., 1753. North American East, South China and North Vietnam.

• Whole leaves, rarely 2-lobed. Introrious antennas or latrorsas. Non-samaroid carpals in fruit, dehiscent or circumcisile, if indehiscent, forming a sincarpo:

Magnolia L., 1753. East and South Asia, Indonesia and New Guinea, North and South America.

Etymology

The genus is named after Pierre Magnol, a botanist from Montpellier, France. The first identified species of this genus was Magnolia virginiana, found by missionaries sent to North America in the 1680s. Magnolia grandiflora was also found there, as early as the XVIII.

Evolution

Magnoliaceae are an ancient family that evolved before bees appeared, so the flowers developed in such a way that they could be pollinated by beetles. As a consequence, they have hard carpels to prevent deterioration. Fossilized specimens of Magnolia acuminata dating back 20 million years have been found, and plants belonging to the Magnoliaceae family dating back 95 million years have been identified.

Another distinctive feature of magnolias is the absence of sepals or petals; instead they have tepals, a term that was coined to refer to this intermediate element.

Fossils

Representatives of this family have been known since the Late Cretaceous, with traces of them remaining throughout the northern hemisphere (eg Archaeanthus from the Cenomanian, 98 Ma). The seeds of Magnolia are common in the deposits of the European Tertiary. The North American species are considered to be survivors of the Pleistocene, during which the European representatives became extinct.