Prickly silk

One plant from today’s visit to the cactus garden at Stanford: the silk floss tree, Ceiba speciosa (Ciba /síbǝ/), with trunk and branches studded with prickles and with still fresh palmate leaves (with 7 leaflets per leaf on this particular tree).

From Wikipedia:

The silk floss tree (Ceiba speciosa, formerly Chorisia speciosa), is a species of deciduous tree native to the tropical and subtropical forests of South America. It has a host of local common names, such as palo borracho (in Spanish literally “drunken stick”), samu’ũ (in Guarani) or paineira (in Brazilian Portuguese). In Bolivia it is called Toborochi, [which] means “tree of refuge” or “sheltering tree”. It belongs to the same family [Malvaceae] as the baobab and the kapok.

The natural habitat of the silk floss tree is the north-east of Argentina, east of Bolivia, Paraguay, Uruguay and southern Brazil. It is resistant to drought and moderate cold. It grows fast in spurts when water is abundant, and sometimes reaches more than 25 metres (82 ft) in height. Its trunk is bottle-shaped, generally bulging in its lower third, measuring up to 2 metres (7 ft) in girth. The trunk is also studded with thick, sharp conical prickles which deter wild animals from climbing the trees. In younger trees [like the one at Stanford], the trunk is green due to its high chlorophyll content, which makes it capable of performing photosynthesis when leaves are absent; with age it turns to gray.

(#1) The thorny trunk on a young tree

The branches tend to be horizontal and are also covered with prickles. The leaves are composed of five to seven long leaflets.

(#2) Leaves of 7

The flowers are creamy-whitish in the center and pink towards the tips of their five petals. They measure 10 to 15 centimetres (4 to 6 in) in diameter and their shape is superficially similar to hibiscus flowers [to which they are related].

(#2) An especially showy flower

Their nectar is known to attract insect pollinators, as well as hummingbirds. C. speciosa flowers are in bloom between February and May (in its native Southern Hemisphere), but can also bloom at other times of the year. The flowers of the related C. chodatiiare similar in form and size, but their color goes from creamy white centers to yellow tips. As a deciduous tree, it is completely bare of leaves and flowers during the winter months, especially when growing outside of its native South America habitat.

The fruits are lignous ovoid capsules, 20 centimetres (8 in) long, which contain bean-sized black seeds surrounded by a mass of fibrous, fluffy matter reminiscent of cotton or silk.

The silk floss tree is cultivated mostly for ornamental purposes. Outside of private gardens around the world, it is often planted along urban streets in subtropical areas such as in Spain, South Africa, Australia, northern New Zealand and the southern USA, although its prickled trunks and limbs require safety buffer zones, especially around the trunks, in order to protect people and domesticated animals from its prickles.

On the mallow family (the Malvaceae) on this blog: in a 3/27/13 posting “Abutilon and its relatives”. Not just baobab and kapok, but also hibiscus, hollyhock, Rose of Sharon, mallow, sidalcea, lavatera, abutilon, cotton, okra, cacao, and durian.

To come, in other postings: about the more famous Ceiba, C. pentandra, the kapok tree; about an entirely unrelated plant, mesquite, which Juan Gomez and I ran across while trying to identify the prickly tree at Stanford; and about some other fabulous plants we saw at Stanford (time to get Cereus).

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