Chorisia speciosa

This South American tree has a brilliant display of pink, lily-like flowers. It blooms best during the month of October, adding a touch of color at a time when most blooms are fading.

Check out this beautiful street scene

The white bloom is from another variety (Chorisia insignis

Silk floss tree.  Bombacaceae. Tree to 50 ft. with purple flowers. Spectacular 5-6 inch purple flowers.   Native to Brazil and Argentina.  Hardy in Zone 9b

Favorita food of the giant moth ARSENURA ARMIDA

Description: Mainly evergreen but will go deciduous briefly when they flower. Oval shaped medium sized tree growing to 30 to 60 ft tall and 20 to 40 ft wide. Fast rate of growth when young then slows down. Beautiful flowering tree in fall with showy pink to rosy colored blossoms. Trunk is stout, green in color and usually is armed with thick, heavy spines. Leaves are palmately compound with long petiole. Five leaflets per leaf. Fruit is a large pod appearing in spring. Pod opens and emits cotton like material. Used as a background tree, for naturalizing, accent, and specimen. Prefers a well drained soil and likes summer water. Is considered to be half hardy. Trunk is usually enlarged at base. Cotton is used as stuffing material like pillows. Tree may go deciduous in autumn or when temp goes below 27 degrees F.


Seeds of the South American kapok tree (Ceiba pentandra) and floss silk tree (Chorisia speciosa) are embedded in dense masses of silky hairs inside large woody capsules. This undoubtedly helps to disperse the seeds when seed-bearing masses of hair are carried by the wind. In tropical regions of the New World, the kapok grows into an enormous rain forest tree with a massive buttressed trunk. Kapok hairs are coated with a highly water-resistant, waxy cutin layer. The empty lumen (cavity) inside each hair is larger the cotton hairs; hence, the hairs are lighter. Unlike cotton hairs, kapok is difficult to spin and is not made into textiles. It is used primarily as a waterproof filler for mattresses, pillows, upholstery, softballs, and especially for life preservers. A kapok-filled life jacket can support 30 times its own weight in water.

Timber Info - 

Chorisia speciosa St. Hil.(samu'u)

Nomenclature etc. BOMBACACEAE. Trade and local names: samu'u, palo borracho (PY); paneira, paneira-branca, paina de seda, barriguda, arvore-de-paina (BR); paneira (USA). Status of protection under CITES regulations: not protected.

Description based on: 2 specimens. Tree. Geographic distribution: temperate South America.

General. Growth ring boundaries distinct, growth ring limits demarcated by bands of thicker walled fibres and thickened rays. Basic specific gravity 0.27 g/cm³.

Vessels. Vessels present. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Vessel outline rounded. Two distinct vessel diameter classes absent. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 12–16 µm, large, not vestured. Vessel-ray pits with reduced borders or apparently simple, different from intervessel pits, rounded or angular and horizontal to vertical, of two distinct sizes or types in the same ray cell, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels present, thinwalled. Other deposits in heartwood vessels present.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled. Fibre pits common in both radial and tangential walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, not banded. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (3–)4. Unlignified parenchyma absent.

Rays. Rays present, multiseriate, also if only few, (1–)3–12(–22) cells wide, commonly 3–5 cells wide, commonly 5–10 cells wide, and commonly more than 10 cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of two distinct sizes. Rays composed of two or more cell types. Heterocellular rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 1 and 2–4. Sheath cells present. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure present, some rays storied, some not, axial parenchyma storied, vessel elements storied, fibres storied. Arrangement of tiers regular (horizontal or straight). Number of ray tiers per axial millimetre 2.

Secretory structures. Oil and mucilage cells absent. Intercellular canals absent. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic, located in ray cells. Crystal-containing ray cells upright and/or square, upright and/or square ray cells not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Silica not observed.       H. G. Richter and M. J. Dallwitz (2000 onwards). 'Commercial timbers: descriptions, illustrations, identification, and information retrieval.' In English, French, German, and Spanish. Version: 4th May 2000.

Avocado-like fruits of Chorisia speciosa


C. speciosa fruit wall hairs


C. speciosa buds and flowers

Cotton on a Tree

A particular tree species in West Los Angeles evokes some of the strangest conversation. "Is that a giant avocado tree?" "It looks like cotton coming from that tree!" "Look at the sharp spines on that trunk!" "The flowers are so beautiful--what is that tree?" The tree is Chorisia speciosa, or floss-silk tree. Many call it the silk-floss tree, but the way to remember it is alphabetically, f before s. Better yet, use the botanical binomial and impress your friends!

Chorisia speciosa is a member of the Bombacaceae, or cotton-tree family, which includes 30 genera and approximately 180 species, mostly large trees that grow in seasonal dry forests and grassy woodlands of the tropics and subtropics, especially in the Americas. Most photographed among the Bombacaceae, however, is the famous baobab or dead rat tree, Adansonia digitata, an elephantine tree of African savanna woodland with a massively enlarged, bottle-shaped, gray trunk and short, dumpy branches sticking into the air like thick roots. To explain its monstrous appearance, Kenyans say that the devil planted this tree upside down. One baobab has been reported to have a circumference of sixty-two feet, and some Africans have speculated that several of these trees may be up to 5,000 years old! In some cases, the tree develops a hollow center, wherein bats can roost--which is convenient because its white flowers, about six inches across, are pollinated by bats. Moreover, the fuzzy fruits, which may become up to eighteen inches long, are pendent on long pedicels, giving the appearance of hanging dead rats! MEMBG has one small baobab, which will be planted out this coming spring.


But let's return to the floss-silk tree, a native of southern Brazil and Argentina, and a popular L.A. tree since the 1970s. This plant grows rapidly during its early years, and then growth slows after the branched canopy has formed. The leaves are alternate and palmately compound, in some Southland locations totally deciduous and in others semi-deciduous, retaining branches of leaves. But what catches the eye are the grass-green bark and branches and the trunk studded with persistent, stout, gray "spines." Botanically speaking, these sharp projections are termed trunk prickles, bark prickles, or stem emergences--that is, outgrowths from internal stem tissues. (Spine is a term now reserved for a modified stem, leaf, or root primordium.) In C. speciosa, stem emergences are absent on new stems but erupt from cortex on two-year-old stems at the internodes. Thereafter, as cells divide at the base, each emergence gets taller and wider, eventually becoming one to one-and-one-half inches high and often one inch wide. As the trunk becomes slightly inflated with water-storing cells ("a bottle tree"), the bark stretches. On stretched bark, green stem patches become furrows separated by newer gray bark. Circular scars on the trunk bark show where emergences have been pried off or shed.

Locally, you can view average specimens of C. speciosa at the corner of Sunset and Beverly Glen, and at Hilgard and Le Conte, where a pair forms an arborescent entrance to MEMBG. But if you really want to see a prime specimen, come to the Malesian Rhododendron section and look upward. At the edge of the collection, opposite our Blakea gracilis, is a sixty-foot giant, resembling a mature individual in nature with its bottle-like trunk unbranched for forty feet and supporting a symmetrical crown. This plant is best appreciated during winter, when it is totally leafless, so your attention focuses on the green- and gray-striped bark and the immature green fruits--like gigantic avocados--suspended overhead.

Obviously, to view flowers up close you will need to use one of the shorter street trees! Flowers of C. speciosa, which appear in late summer and early fall, are extremely showy and have been compared with those of certain lilies and orchids. A fully open flower may be six inches across, consisting of five distinct (not fused), thick petals. On a single tree, the color tone of petals is light orchid-pink, purplish rose, dark purple, or burgundy, typically marked with ivory or white and spotted brown on the lower half. One grafted clone called 'Los Angeles Beautiful' has wine-red flowers, and 'Majestic Beauty' has rich pink flowers. The pistil consists of a superior ovary with five chambers (locules) having many ovules, a long white style, and topped by a hemispherical, rose-colored stigma. A tubular column formed by the fusion of five stamens (filaments) surrounds the style. The filaments bear the massive anthers, which are loaded with pollen. The features of large size, thick parts to avoid mechanical damage, and copious pollen indicate that bats would be appropriate pollinators for these trees in their natural habitats.

The less commonly cultivated tree C. insignis has similar floral structure, but its petals are white with yellow at the base. This species flowers later than its better-known cousin, often in December and January, but C. insignis is equally magnificent (even if its common name is drunken tree!) and should be more widely grown.

The fruit of both species of Chorisia, in fact of most Bombacaceae, is a capsule. It is oblong or somewhat pear-shaped and may grow to six inches in length. While it is developing and even later when it is large and green, one can often observe a persistent style at the end of the fruit. At maturity, five valves of the capsule fall away (the fruit is dehiscent) to reveal the locules, now filled with five elongate masses of silky white hairs. Floss-silk resembles cotton but, unlike cotton, is attached just below the seeds, which are hidden by the silk. When released, these silky hairs help to disperse the seeds in strong winds in the canopy, but in Los Angeles, instead, they can litter a lawn or planting bed.

Among Bombacaceae, the most famous economically important fruit hair has been harvested from Ceiba pentandra, the kapok or silk-cotton tree. Probably few people in California have ever heard of kapok, a towering emergent of lowland neotropical forests, often reaching fifty meters in height and forming enormous, flaring root buttresses that prevent the tree from snapping at the base. Unlike cotton, kapok cannot be woven into cloth, but formerly it was widely used for stuffing pillows, bases and balls for baseball and softball, mattresses, and, especially, life jackets. In fact, during World War II, a U.S. sailor would commonly refer to his life jacket as a "kapok." Since the war, however, synthetic fibers have replaced kapok for these traditional uses.

Along the main service road at MEMBG, located just south of The Nest, is a recently transplanted small specimen of Ceiba aesculifolia, a native of western Mexico. The gardeners had to hastily relocate this tree from its former bed when equipment repairs were required near the corner of the Botany Building, and fortunately it is thriving in its sunny new home. Like chorisias, this plant has formidable stem emergences and palmately compound leaves, which look like leaves of Aesculus (buckeye).

Also growing above the rhododendrons are two prized specimens of the shaving-brush tree, Pseudobombax grandiflorum. This species has the green and gray stripes on its bark but totally lacks the stem emergences. Its flowers are unusual in having a pincushion of showy stamens rather than showy petals.

There are beautiful flowering trees elsewhere in this family, as well as other species that are useful to humans. Bombax, which includes the red silk-cotton tree, is the largest genus (about sixty species). Ochroma pyramidale is not only a key pioneer tree species of disturbed neotropical rain forests, but also the source of balsa, the lightest of all commercial woods. Durio includes the tree that produces the durian, a large, highly prized fruit that is famous for its delicate flavor but disagreeable odor. Like related families Malvaceae, Sterculiaceae, Urticaceae, and Tiliaceae, Bombacaceae have high-quality "bast" fibers in the inner bark, which preserve the integrity of the bark but can be stripped off in ribbons and twisted into cord for fishing nets.

Little scientific research has been done to understand the adaptations of these tropical tree species, which often live in communities with unrelated plants that also are thorny and have green bark. Yet this is a prime family to study for learning about the importance for survival, if any, of bark photosynthesis; the possible role of stem emergences in protecting plants from herbivores; and the influence that stem water storage has on surviving drought and initiating growth after the dry season.

Anyway, if you are looking to add a tree to your garden, why not consider one from the showy-flowered Bombacaceae? Keep in mind, however, that Chorisia wood is soft, and branches may break off in strong winds, and also that its roots can heave pavement. Still, these plants add great color to a neighborhood at the end of the calendar year.

Rebecca Bonney, MEMBG Docent