Sansevieria Thunb. (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Sansevieria Thunb.

Protologue: Prodr. fl. cap. 29: 65 (1794).

Family: Dracaenaceae

Chromosome number: x= 20, 21;S. roxburghiana,S. trifasciata: 2n= 40

Major species and synonyms

• Sansevieria roxburghiana J.A. Schultes & J.H. Schultes, Syst. veg. 7, 1: 357 (1829), synonyms: S. zeylanica auct. non (L.) Willd. (1799), Cordyline roxburghiana (J.A. Schultes & J.H. Schultes) Merrill (1923).

• Sansevieria trifasciata Prain, Bengal. plants 2: 1054 (1903), synonyms: S. guineensis auct., S. zeylanica auct. non (L.) Willd. (1799).

Vernacular names

• General: bowstring hemp (En)
• Philippines: tigre (Tagalog, Bisaya), buntot tigre (Tagalog).

• S. roxburghiana : Indian bowstring hemp (En)
• Thailand: waan laai, waan lin hia (central), haang suea (Bangkok).

• S. trifasciata : African bowstring hemp, snake plant, mother-in-law's tongue (En). Chanvre d'Afrique (Fr)
• Indonesia: lidah buaya (Malay), letah bayawak (Sundanese), lidah mertua
• Malaysia: lidah buaya
• Thailand: waan hang suea (general), waan chakhe (northern), lin naakkharaat (Bangkok)
• Vietnam: hổ vĩ, lưỡi cọp sọc.

Origin and geographic distribution

Sansevieria comprises about 100 species indigenous to tropical Africa and Asia. Several Sansevieria spp. have been introduced throughout the tropics as fibre plants or as ornamentals and have often naturalized. S. roxburghiana occurs wild and cultivated in India and is frequently grown as an ornamental elsewhere. S. trifasciata is native to tropical Africa and is widely grown as an ornamental, e.g. in Indo-China, Indonesia (Java) and Malaysia. It is cultivated as a fibre plant in tropical regions and has often escaped from cultivation. Both S. roxburghiana and S. trifasciata are reported to be cultivated for their fibre in the Philippines.

Uses

Fibre from the leaves of Sansevieria is used locally for making string, rope, nets, mats, hats, backs for matting, hammocks and coarse fabrics, mainly in India and Africa. The name bowstring hemp stems from the longtime use of Sansevieria fibre for bows in Africa and India. Sansevieria fibre is also used for paper production. In South-East Asia Sansevieria fibre is locally used, but it is not always clear which species are involved. In the Philippines Sansevieria fibre is mixed with pineapple ( Ananas comosus (L.) Merr.) fibre in weaving fabrics. In Vietnam Sansevieria fibre is sometimes used for making string. Good-quality S. trifasciata fibre was produced in Singapore and Malaysia in the early 20th Century, but interest was short-lived and commercial production never occurred.

In Singapore and Indo-China the warm juice of S. trifasciata leaves is dropped into the ear as a treatment for earache. In Indo-China the juice of fresh leaves is used to treat pharyngitis and hoarseness. In Perak (Malaysia) a warm decoction of the leaves is applied to itchy skin. In Java the sap of S. trifasciata has been used to promote hair-growth. In the Philippines roasted Sansevieria leaves serve as an emollient. The pulp remaining after mechanical fibre extraction from S. trifasciata leaves contains gelling substances which are used in India as a base for cosmetics and medicines. Sansevieria is grown worldwide as an ornamental plant.

Production and international trade

Sansevieria fibre is mainly used locally. At various times attempts have been made to develop commercial production, especially when there were shortages of other fibres such as sisal ( Agave sisalana Perrine) and abaca ( Musa textilis Née), but most of these have been unsuccessful. During and after the Second World War studies were made in the United States to examine the potential of various Sansevieria spp. to replace sisal and abaca as a source of marine fibre. S. trifasciata was considered the most suitable species, because of its leaf length, fibre content and tolerance to cold. No recent production and trade data for Sansevieria are available.

Properties

In cross-section, Sansevieria leaves are divided into a peripheral region of green chlorenchyma tissue and a central region of water-storage tissue. Fibre bundles are present throughout the leaf but are largest and most prominent in the chlorenchyma. In general Sansevieria fibre strands are 45-180 cm long (depending on leaf length), creamy white, rather soft and lustrous, with good strength, elongation and resistance to salt water microorganisms, but species differ in fibre quality. The ultimate fibre cells are 1-7 mm long, with a diameter of 12-40 μm. Individual fibres are approximately cylindrical in shape, with rounded ends. In cross-section they are polygonal, with thin cell walls and a very large, oval to polygonal lumen. Most fibre cells have only a primary cell wall or a very thin secondary cell wall. S. trifasciata leaves from experimental stands in Florida yielded on average about 1.6% decorticated dry fibre. The leaves of S. trifasciata contain steroidal saponins and pregnane glycosides.

Adulterations and substitutes

If produced commercially, Sansevieria fibre would have to compete mainly with sisal fibre, which is less fine but stronger and less brittle. Furthermore the leaves of many Sansevieria spp. are shorter than those of sisal and the fibre recovery is lower. Sansevieria fibre also faces competition from abaca and synthetic fibres.

Description

Stemless, often xerophytic, perennial herbs with leaves in a rosette borne on a subterraneous rhizome. Leaves erect, flat or concave or terete, fleshy, fibrous, often variegated. Inflorescence a terminal, erect, branched raceme, with bisexual, often fragrant flowers fascicled in the axils of scarious bracts; pedicels articulate; perianth tubular with 6 narrow, equal, spreading or recurved lobes; stamens 6, inserted in the top of the perianth-tube, equalling the perianth or often much exserted, filaments filiform, anthers versatile; pistil with superior, sessile, broad-based, 3-locular ovary, (cells 1-ovuled), style long filiform, stigma slightly thickened. Fruit a 1-3 seeded berry.

• S. roxburghiana . Leaves 6-24 over the life cycle, those of juvenile plants and the outer ones of a tuft spreading, others usually ascending; blade stiff, linear-oblong, 20-60 cm × 1-2.5 cm, deeply concave channelled down the face, rounded or slightly keeled on the back, margins entire and with age becoming narrowly whitish, apex tapering to a soft point, green, with transverse darker green rather regular bars on both sides and with 6-11 longitudinal dark green lines on the undersurface and often 1-3 on the upper. Raceme spike-like, 30-75 cm long (peduncle included), lower part with 4-5 erect acuminate sheaths 1-2 cm long; flowers 3-5 in a cluster; pedicel up to 8 mm long, jointed near the middle; tube 6-7 mm long; lobes linear, 8-9 mm long, greenish tinged with purple; stamens about 7 mm long, anthers dorsifixed; ovary obovoid, 1.5 mm long, stigma simple, obscurely lobed. Berry globose, up to 6 mm in diameter.

• S. trifasciata . Rhizome sympodial, robust, yellowish-red. Leaves in each plant 2-6, much broader than thick, fleshy to rigidly coriaceous, dark green, with numerous very conspicuous, light or greyish-green, irregularly confined transverse bonds, in the normal form with a narrow dark green margin; large leaves linear-lanceolate, 40-175 cm × 2.5-9 cm, base channelled, margins entire, apex acute. Raceme erect, 40-75 cm long (peduncle included); flower-fascicles scattered or arranged group-wise; pedicel 6-8 mm long, articulated at about the middle; perianth 2.5-3 cm long, greenish-white, scented, divided just below the middle; lobes narrowly linear, broadening towards the greenish tip; stamens 7-8 mm long; style 15-18 mm long. Berry globose, 7-9 mm in diameter, orange, 1-2-seeded. Seed globular-ellipsoid, 6-7 mm × 5 mm, cream-brown.

Growth and development

From the planted Sansevieria rhizome or seed a juvenile rosette develops, which later produces upright leaves. If leaf cuttings are planted, the rosette stage is usually not produced, except when basal leaf parts are used. The number of leaves produced over the life cycle varies with the species, but generally ranges from 8-15. In Java S. trifasciata flowers year-round, with the flowers expanding and becoming fragrant towards the evening.

Sansevieria uses the Crassulacean Acid Metabolism (CAM) pathway. CAM plants are able to fix CO₂at night and to photosynthesize with closed stomata during the day, thus minimizing water loss.

Other botanical information

Sansevieria has been classified in the Liliaceae , the Agavaceae , and more recently, together with Dracaena L. in the Dracaenaceae , the latter option being supported by chloroplast DNA studies. Most probably, in the future Sansevieria will be united with Dracaena and consequently all Sansevieria names will have to be recombined in Dracaena .

In the literature, S. trifasciata and S. roxburghiana have often erroneously been called S. zeylanica . The true S. zeylanica (L.) Willd. ("Ceylon bowstring hemp") seems to be native to and cultivated only in Sri Lanka and it is assumed here that it does not occur in South-East Asia although some doubt remains. A thorough revision of the genus is badly needed.

S. trifasciata Prain "Laurentii" (syn. S. trifasciata Prain var. laurentii (De Wildem.) N.E. Br., S. zeylanica laurentii hort.), with broadly yellow-margined leaves, is the leading Sansevieria cultivar in commercial horticulture. It is found worldwide as an ornamental potted plant and is occasionally cultivated as an ornamental in Java. Other ornamental cultivars of S. trifasciata include "Bantel's Sensation", "Craigii", "Compacta" and the dwarf cultivars "Hahnii", "Silver Hahnii", "Golden Hahnii", "Hahnii Variegated" and "Loop's Pride".

Other Sansevieria species which are sometimes used for their fibre and which may occasionally be cultivated in South-East Asia include: S. cylindrica Bojer ex Hook., in tropical eastern and western Africa; S. ehrenbergii Schweinf. ex Baker, in tropical eastern Africa and Yemen; S. hyacinthoides (L.) Druce (syn. S. guineensis (L.) Willd.), in tropical and southern Africa; S. liberica hort. ex Gérome & Labroy, in tropical Africa; S. longiflora Sims, in tropical Africa and also cultivated in Jamaica, Trinidad and southern Florida; and S. senegambica Baker, in tropical West Africa. S. hyacinthoides has been commercially produced in Mexico, with exports to the United States.

Ecology

Some Sansevieria species grow in arid regions with an annual rainfall of less than 250 mm, whereas others occur in evergreen tropical forest with an annual rainfall over 2000 mm. They are usually able to survive in adverse conditions, but for commercial production a warm, moist climate and well-drained, somewhat calcareous soils are recommended. Shading is sometimes recommended, but its favourable effect may be due more to its influence on soil moisture and nutrient status than to a direct effect on plants. In Java S. trifasciata is found up to 1000 m altitude.

Propagation and planting

Sansevieria can be propagated by rhizome division, suckers or leaf cuttings. Propagation by seed is also possible, but some Sansevieria species rarely produce seed. S. trifasciata , however, readily produces seed. S. roxburghiana as well as S. trifasciata are easily propagated by leaf cuttings. In a Philippine study with S. trifasciata cv. "Laurentii", rhizomes or suckers gave earlier rooting and better growth than leaf cuttings. Because the number of leaves produced per plant is low compared to e.g. sisal, Sansevieria has to be planted at closer spacing, e.g. 1 m × 0.5 m. Seeds should be sown at a depth of about 2.5 cm and rhizome parts should be planted at 5 cm depth.

In horticulture leaf cuttings are the preferred method of propagation for Sansevieria , because it takes longer to obtain many plants from rhizome division. Leaf cuttings may be as short as 5 cm, but the longer the leaf, the sturdier the offspring and therefore 20-25 cm long cuttings are recommended. Cuttings form roots in about a month, and about 3 months after planting rhizomes develop, which produce upright leaves. Longer leaf cuttings will usually produce more than one offshoot. It is sometimes recommended that complete leaves be used, from which the offshoots may be severed and the leaf left to produce more offshoots. Cut leaves may be left unplanted for several months, after which they are still able to form offshoots. Leaf cuttings must be placed with the basal portion in the ground, because roots will not form if the tip is put in the ground. Cuttings from the leaf tips give the best results. Variegated plants often revert to a green colour when propagated from leaf cuttings.

In vitro micropropagation of Sansevieria is also feasible, making it possible to obtain a large number of plants in a short time from a small amount of plant material. Plant regeneration has been achieved from leaf explants of S. trifasciata and its cv. "Laurentii".

Husbandry

Sansevieria is easy to cultivate. Weeding may be done until crop establishment, after which weed growth is effectively suppressed by the crop. Sansevieria is said to respond well to fertilizers and mulching, but no quantitative recommendations are available.

Diseases and pests

No information exists on diseases and pests affecting Sansevieria in South-East Asia. S. roxburghiana in India is reported to be susceptible to the fungus Sclerotium rolfsii .

Harvesting

Sansevieria is usually ready for harvest after 18-30 months, and the regrowth may be harvested at intervals of about 24 months. The leaves are cut manually.

Yield

With 1 harvest every 2 years, the average annual dry fibre yield of S. trifasciata in Florida (United States) was estimated to be about 2 t/ha and that of the hybrid "Florida H-13" ( S. trifasciata × S. deserti N.E. Br.) up to 3.1 t/ha. No information exists on Sansevieria yields in South-East Asia.

Handling after harvest

Sansevieria fibres are removed by hand or by mechanical means. In hand-processing, the fresh or retted leaves are scraped to remove all extraneous matter from the fibre. Using raspadors 75–90% of the fibre in the leaves has been recovered as clean dry fibre suitable for marine cordage. In a Philippine study various methods of extraction of S. trifasciata fibre were compared: machine decortication with a Mayon decorticator, retting for 2 weeks, and the "sipit" method, in which the leaves are gently pounded, pressed between a bamboo split ("sipit"), and the fibres pulled through the sipit to remove the pulp, after which they are washed thoroughly and dried in the shade. There was no difference in the length of the fibre strands obtained by the different methods, but the fibre recovery was highest with the retting method, slightly lower with machine decortication and much lower with the sipit method. The tensile strength of fibre obtained from machine decortication or sipit method was three times as high as that of fibre obtained by retting. In India the fibre of S. roxburghiana ("murva fibre") is extracted by scraping fresh or retted leaves.

Genetic resources

About 50 Sansevieria accessions are kept at the United States Department of Agriculture (USDA) Subtropical Horticultural Research Unit in Miami, Florida (United States).

Breeding

Breeding programmes were carried out in the 1950s in the United States to develop Sansevieria types suitable for fibre production in Florida. Fertile hybrids were obtained from interspecific crosses between diploid species ( S. aethiopica Thunb., S. deserti, S. ehrenbergii , S. parva N.E. Br. and S. trifasciata ), whereas sterile hybrids evolved from crosses between S. trifasciata and the tetraploid S. cylindrica . The programme resulted in the release of the hybrid "Florida H-13" ( S. trifasciata × S. deserti ) for fibre production. At present no breeding programmes of S. roxburghiana and S. trifasciata as fibre plants are known to exist.

Prospects

Sansevieria is a useful local source of fibre, but the prospects for commercial fibre production are bleak, in view of the competition from sisal, abaca and synthetic products. Sansevieria will remain important for ornamental purposes, especially S. trifasciata with its many cultivars.

Literature

• Agpaoa, B.P., 1953. Three methods of extracting the fiber of Sansevieria trifasciata. The Philippine Agriculturist 37(7): 399-406. 2 Brown, N.E., 1915. Sansevieria. Royal Botanic Gardens of Kew Bulletin of Miscellaneous Information 5: 185-261. 3 Chahinian, B.J., 1986. The Sansevieria trifasciata varieties. A presentation of all cultivated varieties. Trans Terra Publishing, Reseda, California, United States. 109 pp.
• Gangstad, E.O., Joyner, J.F. & Seale, C.C., 1951. Agronomic characteristics of Sansevieria species. Tropical Agriculture 28: 204-214. 5 Joyner, J.F., Gangstad, E.O. & Seale, C.C., 1951. The vegetative propagation of Sansevieria. Agronomy Journal 43: 128-130.
• Menzel, M.Y. & Pate, J.B., 1960. Chromosomes and crossing behavior of some species of Sansevieria. American Journal of Botany 47(4): 230-238. 7 Orteza, E.M., 1954. Methods of propagating Sansevieria. The Philippine Agriculturist 38(4-5): 392-397. 8 Wilson, F.D., Joyner, J.F. & Fishler, D.W., 1969. Fiber yields in Sansevieria interspecific hybrids. Economic Botany 23: 148-155.

Authors

T.N. Praptosuwiryo