ANNONACEAE: Largest Family of Magnoliales(order)

Sanjeet kumar
sanjeet.biotech@gmail.com

Annonaceae,  the custard-apple, or annona, family, the largest family of the magnolia order of family of flowering plants consisting of trees, shrubs or rarely lianas. Seven genera, Annona, Anonidium, Rollinia, Uvaria, Melodorum, Asimina and Stelechocarpus produce edible fruits. The family is concentrated in the tropics, with few species found in temperate regions. About 900 species are Neotropical, 450 are Afrotropical, and the other species Indomalayan. They are trees, shrubs, or climbers, wood and leaves often aromatic; indument of simple or less often (Uvaria, Annona) stellate hairs. Leaves alternate, normally distichous. Stipules absent. Petiole usually short; leaf blade simple, venation pinnate, margin entire. Inflorescences terminal, axillary, leaf-opposed, or extra-axillary [rarely on often underground suckerlike shoots]. Flowers usually bisexual, less often unisexual, solitary, in fascicles, glomerules, panicles, or cymes, sometimes on older wood, usually bracteate and/or bracteolate. Sepals hypogynous, [2 or]3, imbricate or valvate, persistent or deciduous, rarely enlarging and enclosing fruit, free or basally connate. Petals hypogynous, 3–6(–12), most often in 2 whorls of 3 or in 1 whorl of 3 or 4[or 6], imbricate or valvate, sometimes outer whorl valvate and inner slightly imbricate. Stamens hypogynous, usually many, rarely few, spirally imbricate, in several series; filaments very short and thick; anther locules 2, contiguous or separate, rarely transversely locular, adnate to connective, extrorse or lateral, very rarely introrse, opening by a longitudinal slit; connectives often apically enlarged, usually ± truncate, often overtopping anther locules, rarely elongated or not produced. Carpels few to many, rarely solitary, free or less often connate into a 1- locular ovary with parietal placentas; ovules 1 or 2 inserted at base of carpel or 1 to several in 1 or 2 ranks along ventral suture, anatropous; styles short, thick, free or rarely connate; stigmas capitate to oblong, sometimes sulcate or 2-lobed. Fruit usually apocarpous with 1 to many free monocarps, these sometimes moniliform (constricted between seeds when more than 1-seeded), often fleshy, indehiscent, rarely dehiscent (Anaxagorea, Xylopia), and often with base extended into stipe, rarely on slender carpophores (Disepalum), less often syncarpous with carpels completely connate and seeds irregularly arranged and sometimes embedded in fleshy pulp. Seeds 1 to many per monocarp or many per syncarp, often arillate; endosperm copious, ruminate; embryo minute, near hilum. About 129 genera and over 2,300 species: tropics and subtropics, especially in Old World; 24 genera (one endemic, three introduced) and 120 species (41 endemic, 11 introduced) in China.  The flowers often open before the petals have fully expanded making it easy to underestimate floral dimensions.  One of the major studies of the Annonaceae of tropical Asia was by Suzanne Jovet-Ast (1914–2006), who published an account of the Indochinese species under her maiden name, Ast (Fl. Indo-Chine, Suppl. 1: 62–121. 1938). Unfortunately, she failed to provide Latin descriptions for her many new taxa, none of the names of which was therefore validly published. Her new combinations were validly published, however, and she did subsequently validate a few species of Goniothalamus under her maiden name; but she did not validate most of her new species until after she married and took up the name “Jovet-Ast.” These later names form the major part of all her publications, so we have chosen to cite her as “Jovet-Ast [“Ast”]” for those taxa validated under her maiden name.

Tsiang Ying & Li Ping-t’ao. 1979. Annonaceae. In: Tsiang Ying & Li Ping-t’ao, eds., Fl. Reipubl. Popularis Sin. 30(2): 10–175.

1a. Fruit syncarpous, with completely united carpels and seeds embedded in pulp (usually cultivated as fruit trees).

2a. Outer petals usually free, abaxially flat ........................................................................................ Annona

2b. Outer petals connate at base, abaxially spurred or winged ....................................................Rollinia

1b. Fruit apocarpous, with carpels forming free, often stipitate, monocarps.

3a. Sepals or inner petals and sometimes also outer petals clearly imbricate; stellate hairs often present.

4a. Trees or self-supporting shrubs; stellate hairs absent; sepals imbricate; petals valvate or very

       minutely imbricate; ovules 1 per carpel ..............................................................Trivalvaria

4b. Climbing shrubs; stellate hairs present; sepals valvate; inner petals and sometimes also outer

      Petals imbricate; ovules 2 or more per carpel.

5a. Petals spreading at anthesis; torus depressed .......................................Uvaria

5b. Petals incurved at anthesis, not opening widely; torus flattened, margin prominent

                ……. Cyathostemma

3b. Sepals and inner and outer petal whorls all valvate or rarely very narrowly imbricate at tip only (only

1 whorl of petals present in Dasymaschalon); simple hairs usually present, less often plant glabrous.

6a. Climbing shrubs.

7a. Peduncles and fruiting pedicels hooklike ...................................Artabotrys

7b. Peduncles and fruiting pedicels not hooklike.

8a. Monocarps ellipsoid, moniliform when more than 1-seeded; petals basally constricted

      to form enclosed floral chamber around stamens and carpels .....................Desmos

8b. Monocarps globose to cylindric, never moniliform; petals not constricted.

9a. Monocarp stipes 5.3–7.5 cm; outer petals usually much larger than inner petals;

      Stamen connectives apically truncate……………………….Friesodielsia

9b. Monocarp stipes 0.3–4 cm; outer petals only slightly larger than inner petals; stamen

                                                  connectives apically acuminate to obtuse ..........................Fissistigma

6b. Trees or erect shrubs.

10a. Petals (2 or)3, in 1 whorl ..........................................................Dasymaschalon

10b. Petals 6, in 2 whorls.

11a. Inner petals basally clawed or stipitate, laminas vaulted and connate into an apical cap

                                     at least initially.

12a. Outer petals 2–7 mm, usually smaller than inner petals and similar to sepals.

13a. Inner petals with a long basal claw, usually apically lozenge-shaped and

        Cohering by their margins into a cap over stamens and carpels, sometimes

        with their tips conspicuously recurved; pedicel 0.2–1.2 cm ..........Orophea

13b. Inner petals with a short basal claw, shallowly saccate, at first cohering by

        Their margins but soon free; pedicel usually 1.4–10 cm………….. Miliusa

12b. Outer petals more than 12 mm, equaling or longer than inner petals, conspicuously

                                                    different from sepals.

14a. Stamens linear-oblong; inner petals each with a short claw…Goniothalamus

14b. Stamens cuneate; inner petals each with a long claw or stipe.

15a. Outer petals longer than inner petals ..................Mitrephora

15b. Outer petals shorter than inner petals .................Pseuduvaria

11b. Inner petals not basally clawed, spreading or connivent and apically 3-edged.

16a. Stamen connectives apically acuminate.

17a. Petals 5–8 cm, linear to linear-lanceolate ...Cananga

17b. Petals 0.7–1 cm, ovate-triangular to ovate-oblong, usually incurved at base

18a. Monocarps dehiscent, stipe clavate; ovules 2 per carpel

               …………………Anaxagorea

18b. Monocarps indehiscent, stipe not clavate; ovules 5–22 per carpel

                                 ..................Alphonsea

16b. Stamen connectives apically truncate, rounded, or broadly 3-angular.

19a. Ovules 1 or 2(or 3) per carpel, basally or nearly basally inserted.

20a. Inner petals concave and incurved to cover stamens; fruiting

 carpels free but usually connivent …………..Popowia

20b. Inner petals spreading; fruiting carpels free and not connivent

21a. Monocarp bases extended into stipes, not articulate at

         base ................... 14. Polyalthia

21b. Monocarps on slender carpophores, articulate between

        apex of carpophore and base of monocarp ....Disepalum

19b. Ovules many per carpel, ventrally inserted.

22a. Flower buds lanceolate, apically long beaked and 3-

        angled; sepals connate at base or beyond into a cup…

        …….Xylopia

22b. Flower buds ovoid, apically rounded; sepals connate at base but not into a cup; petals flat or cucullate; anther locules not transversely septate.

23a. Petals flat; stamen connectives apically rounded

        stigmas subcapitate, not constricted at base;

        monocarps almost sessile ……..Meiogyne

23b. Petals cucullate; stamen connectives apically truncate to subtruncate; stigmas ovoid, constricted at base; monocarps long stipitate ……Chieniodendron

Monophyly and inter-familial systematics have been well supported for Annonaceae by a combination of morphological and molecular evidence. The APG II system places Annonaceae Combined plastid DNA marker and morphological character analysis of Anaxagorea and other Annonaceae and basal angiosperm genera suggest that Anaxagorea is an ancestral clade, sister to the rest of the family. This may confirm the hypothesis that morphological traits shared with other Magnoliales species (such as 2-ranked phyllotaxis, monosulcate pollen, and laminate stamens) represent ancestral characters, while derived characters observed in other genera have evolved independently multiple times. These analyses also support a biogeographic history in which Annonaceae, and perhaps other basal angiosperm clades, originated in South America during the Cretaceous, radiating due to migration events throughout Africa to Asia and Central to North America.  Guatteria, with its approximately 265 species, is the largest genus of Annonaceae, and might be broken into three small genera based on molecular characters from multiple locations.  Tribe Saccopetaleae is another group of Annonaceae that is awaiting review as recent molecular studies suggest that this tribe is not monophyletic at all

Common Uses

The large, edible, pulpy fruits of some members typically called "anona" by Spanish and Portuguese speaking people of the family's Neotropical range, include species of Annona: custard apple (A. reticulata), cherimoya (A. cherimola), soursop/guanábana/graviola (A. muricata), sweetsop (A. squamosa), ilama (A. diversifolia), soncoya (A. purpurea), atemoya (a cross between A. cherimola and A. squamosa); and biriba (Rollinia deliciosa, which may require reclassification under Annona.). The names of many of those fruits are sometimes used interchangeably. Recently, consumption of the neotropical annonaceous plant Annona muricata (soursop, graviola, guanabana) has been strongly associated as a causal agent in "atypical Parkinsonsism." The causative agent, annonancin, is present in many of the annonaceae. It is thought to be responsible for up to 70% of Parkinsonian conditions in Guadeloupe. Exposure is typically through traditional food and "natural" medicines. Asimina triloba (American pawpaw, prairie banana) has an Eastern U.S. distribution, and is currently under agricultural investigation as a commercial crop. The bark, leaves and roots of some species are used in folk medicines. Lancewood is a tough, elastic and heavy wood obtained from the from species of the family Annonaceae located in West Indies and The Guianas. It was often used especially for carriage shafts. It is brought into commerce in the form of taper poles of about 6 metres in length and from 15 to 20 cm in diameter at the thickest end. The black lancewood or carisiri of The Guianas is of remarkably slender form. The Yellow lancewood tree is found in tolerable abundance throughout The Guianas, and used by the Indians for arrow-points, as well as for spars, beams, etc. Some Bowyers use this wood for making longbows but use the term 'lemonwood' or 'degame' to describe the wood the bow is made from. Some species of the family, such as Cananga odorata (ylang-ylang) also have aromatic oil and are used for perfumes or spices.  Some species are also grown as ornamental plants, especially the Indian species Polyalthia longifolia pendula.

Chemical constituents

Pharmaceutical research has found antifungal, bacteriostatic, antimalarial, and especially cytostatic capability of some chemical constituents of the leaves and bark. A large number of chemical compounds, including flavonoids, alkaloids and acetogenins, have been extracted from the seeds and many other parts of these plants. Flavonoids and alkaloids have shown antibacterial properties, and have been used for treatment of medical conditions, such as skin disease, intestinal worms and inflammation of the eye. Potential pharmaceutical products are currently in early experimental trials in animal models and cell-lines.  Acetogenins are thought to have anti-HIV and anti-cancer effects. A wide variety of products have been developed and are available for cancer treatment.  Flavonoids and alkaloids contained in the leaves and bark of several species of the family have shown insecticidal properties

Economic values

Important commercial fruits from Annona spp. (atemoya, cherimoya, custard-apple, ilarma, sugar-apple, sweet sop, sour sop), Artabotrys.  The Annonaceae are woody trees, shrubs and vines comprising about 130 genera and 2,300 species. The leaves are simple, alternate, lack stipules, and generally are distichously arranged in flat sprays. The flowers are bisexual and actinomorphic, possessing 3 whorls of perianth with 3 segments in each whorl.

Annona spp.

The elongated floral axis also bears many helically disposed stamens and several to many simple pistils. All of the floral parts are distinct. The stamens are very short, consisting of the fertile central anther portion, a distal pad of fleshy connective tissue, and a short fleshy basal portion. The stamens are generally so tightly packed on the receptacle that often only the fleshy connective tissue of each is exposed. The pistils each have a superior ovary with one locule and 1-many parietal ovules. Sectioned seeds reveal channels or partitions in the ruminate endosperm. The pistils generally remain distinct and develop into berry-like fruits but sometimes they coalesce into multiple fruits like the custard apple.