Aristolochiaceae

Aristolochiaceae (Aristolochiaceae) are a family of angiosperms of the Piperales order. It consists of 7 genera and about 500 species, which are distributed throughout the tropical and temperate Holarctic regions.

Description

This family presents characteristics such as:

• Perennial, woody, rhizomatous or climbing herbs. Hypocotylene tubes present in some species adapted to strong seasonal climate changes. Eleocytes present in various parts of the plant, especially in the foliar epidermis, with essential oils. Indumento de pelos uniseriados, the apical cell sometimes uncinated.
• Alternate leaves (pseudooposed in Asarum), dísticas, simple, enteros, 2-3-lobuladas, palmatilobadas o pedadas, pecioladas, base frequently cordiforme, without stypules (sometimes there are short axillary branches with sesile scales that appear to intrapeciolar stypules, called pseudoestypules), conduplicated vernation. Anomalytic stomas.
• Such with monopodic or sympathetic branching, the 3-lacunar knots.
• Lonely flowers or ripids, terminals or axillary flowers, often cauliflowers or ramifloras, perfect, usually epigins, rarely semiepigins or almost hypogins, basically trimeras. Perianto univerticilado (2-verticilado en Saruma), usually gamotepalo, 1-3-number, rarely 6-number, actinomorph or zigomorph. Androceo (4-)5-12(-40 or more) stamens in 1-4 verticils, usually 6 or 12 in 1 or 2 verticils, free, or monadelfos, or soldiers in style forming a ginostemo, anteras with 2 extrorous teaks or the almost latrorcenous exteriors, each teak frequently 2-sporangiade, dehiscence by prominent longitudinal, condative. Sync Gynaceum (Apricot Saruma), with 4-6 lóculos, infero or semiinfero, unique style with 3-6 lobes or very branched (separated cells in Saruma), various stigma, non-capitated, dry or humid, papiloso, ovules 4-50(-100) per carpelo, horizontal or pendulum, anthropos, apotropes, bitégmicos, crasinucelates, parietal placentation in the unilocular ovaries, central or axial in the pluriloculars.

Flower of Aristolochia grandiflora.

• Fruit in septic capsule and valve or irregular dehiscence, plurifolicule in Saruma, indehiscent berry, quite dry and thick walls Pararistolochia, schizocarpo in Aristolochia type Euglypha.
• Seeds with abundant endosperm, oily, without starch, sometimes ruminated, very small embryo; rafe sometimes forming an aryloid eleosoma.
• Inapertured, technical, granular-columeled ectexine, except in Saruma (semitected-reticulated with reduced sulcus) and some species Asarum and Isotrema punjabense with polyforated grains or more rarely polycollids, a derivative acquisition.
• chromosomal number: Asarum presents very large chromosomes; 2n = 24-52 tending in advanced forms to 8-28; the following numbers are known: in Asaroideae: n = 6, 12, 13, 18, 20, 26; Aristolochioideae: (4-)6-7(-28). It's supposed to be x = 7.

Ecology

Asarum europaeum.

Some species produce aposematic leaves that mimic those of other plants (eg Passiflora), which appears to be related to the reliance on caterpillars of butterflies of the genus Battus (Papilionidae) of these plants. This adaptation may also be the reason for the palmate-pedal leaves of Isotrema platanifolia and of some Mexican Aristolochia species with variable leaves.

Flowers usually protogynous, pollination normally by dipterans (Fungivora, Ceratopogonidae, Milichiidae, Chloropidae). The flowers frequently carry osmophores to attract pollinators, producing carrion, musky, fruity, moldy or urine odors, developing structures that imitate fungi, with contrasting colors of purple, black and brown with yellow and green, as of decomposing substances; the perianth tube sometimes becomes a trap that retains visitors by small-opening basal narrowings that open into a final chamber (utricle) with spider-like pubescence and nectaries or hookate hairs), slippery oils, or stiff ramentaments that only release them after pollination.

There is autogamy in some species with a simple floral structure, such as Asarum europaeum. Dispersal is mainly myrmecochore in species in which the seed raphe develops an eleosome. In the other species the dispersion is anemochorous and the seeds frequently present wings or membranous expansions. Epizoochory is known in species with small, sticky seeds, such as Aristolochia odoratissima and hydrochory in Aristolochia clematitis, Aristolochia cornuta and Aristolochia weddellii, while endozoochory is documented in Pararistolochia triactina, the pulp of whose fruits smells like bananas and tastes like custard apples.

Most tropical species live in cloud forest habitats, while temperate-zone forms are adapted to seasonal temperature changes. The trophic association with different genera of butterflies (Papilionidae) in different regions is notable, e.g. eg, Battus in North America, Archon and Zerynthia in the Palearctic, and several other genera in East Asia.

Phytochemistry

The subfamily Asaroideae is rich in lignoids in contrast to Aristolochioideae, rich in benzylisoquinoline-based alkaloids, e.g. eg aristolochic acid. flavonols present. The presence of inulin has been reported in Aristolochia.

Uses

Due to the substances with pharmacological activity they contain, the species of this family have played and continue to play an important role in the different pharmacopoeias, mainly Asarum for the essential oils of its rhizomes, rich in sesquiterpenes and phenylpropanoids and the Aristolochioideae due to aristolochic acid, derived from alkaloids of the aporphin type. Aristolochic acid is nephrotoxic and carcinogenic. Its ingestion has been associated with a clinical picture characterized by rapidly progressive renal interstitial fibrosis (Chinese herbal nephropathy) that rapidly leads to chronic renal failure, together with the appearance of urothelial tumors of the upper urinary tract. Traditionally, these substances have been used in obstetrics (hence the genus name Aristolochia, meaning good delivery), and to treat snake and scorpion stings. Although different therapeutic properties have been attributed to the extracts of some of these species, there is no scientific evidence to support this. Some species of Asarum and Aristolochia are grown as ornamentals.

Systematic position

Aristolochiaceae are a primitive group of angiosperms. They have usually been related to the Annonaceae due to the characters that have been shown to be plesiomorphic; due to other characters, such as gamotepalia, monadelphia and the peculiarities of the seeds, it has also been related to the myristicaceae. The structures that related it to the Raflesiaceae, such as the diaphragm, the stylar processes, and the seed coat, have been ruled out as mere convergences by molecular phylogeny analyses, which show that it forms a clade with the Lactoridaceae and Hydnoraceae (Neinhuis et al., 2005, see reference). The APW (Angiosperm Phylogeny Website) considers it to be part of the Piperales order, being the sister group of the Lactoridaceae (cf. AP-website).

Taxa included

Theoretical Introduction in Taxonomy

Flower of Pararistolochia promissa.

The family is clearly divided into two monophyletic subfamilies, clearly separated by numerous characters: Asaroideae and Aristolochioideae.

Asaroideae O.C. Schmidt, 1935: Non-climbing herbs. sympodial growth. Flowers solitary, terminal, hypogynous to epigynous, without constriction (diaphragm) separating the perianth from the ovary. Perianth does not expire after anthesis. It contains two genera, which are distinguished as follows:

• Perianto in 2 verticils. Nearly apocalypse buds. Fruit in ventral dehiscence plurifolicule.

Saruma Oliv., 1889. Southwest of China.

• Perianto in a verticil, rarely the internal verticil present in the form of subulate structures. Sync ovary. Fruit in irregular dehiscence capsule.

Asarum L., 1753. Holártico.

Flower of Isotrema californicum.

Aristolochioideae: Herbs to woody plants, often climbers. monopodous growth. Clearly epigynous flowers, with constriction (diaphragm) separating the perianth from the ovary, if solitary, not terminal. perianth rapidly deciduous after anthesis. The division into tribes and subtribes is highly controversial, but molecular data allow us to distinguish a basal branch (the genus Thottea), a sister group to the rest of the subfamily, composed of two different branches, Isotreme + Endodeca and Pararistolochia + Aristolochia. This last genus has been tentatively divided by some authors, but a general consensus has not been reached (for more details, see Huber, 1993, in references). Genres can be separated using the following key:

• Perianto actinomorfo. Ovary 4-locular.

Thottea Rottb, 1783. South and Southeast Asia, Indonesia, Malaysia, Philippines.

• Perianto zigomorfo. Ovary 5-6-locular.

• Ginostemo 3-lobed. Antennas grouped by couples.

• Sesile or subsesil gynostheme, its fleshy, big segments. Arbustos or subarbustos erect or volubles.

Isotrema Raf, 1819. Tempered and tropical Asia to Sumatra and Java, North and Central America.

• Stamped gynostheme, cupular, its membranous, thin segments. Razomatous herbs.

Endodeca Raf, 1828. Central and Eastern America.

• Ginostemo 5-12-lobed. equidistant antennas.

• Limbo del perianto 3-lobed, seldom 6-lobed. Ginostemo with 6 or more lobes. Indehiscent berry fruit, quite dry and thick walls.

Pararistolochia Hutch. & Dalziel, 1928. Tropical Africa, Southeast Asia, New Guinea.

• Limbo del perianto peltado, 2-labiado or cut obliquely. Ginostemo 5-6-lobed. Fruit capsule or schizocarpo.

Aristolochia L., 1753. Subcosmopolitan, absent from very cold weather.

Taxonomy

The genus was described by Antoine Laurent de Jussieu and published in Genera Plantarum 72–73. 1789.