Botany Photo of the Day

Connor Fitzpatrick is the author of today's entry:

Today's Botany Photo of the Day comes courtesy of dinesh_valke@Flickr (original image). Take a look at his set of additional excellent photos of Bombax ceiba!

Common names for Bombax ceiba, a member of the Malvaceae (also placed in the Bombacaceae), include Indian kapok, the red cottontree, and the simal tree. As dinesh_valke notes in the written accompaniment to his Flickr photo, the fruit of the simal tree produces a silk-like floss often used in pillows, cushions, and blankets.

Bombax ceiba is native to tropical Asia, temperate Asia, and parts of Australia. The trunk and stems of young trees are covered in sharp outgrowths to deter herbivores. I found sources claiming these are spines while others claimed prickles (see here for a clarification) — there is a difference! The mature trees often have wide buttresses for support.

Flowering occurs between March and April for three weeks and fruit is produced quite rapidly in a period of one month. The bisexual flowers require outcrossing for successful fertilization. Flowers of Bombax ceiba illustrate a few floral innovations required for specialized pollination. Raju et al., in Bat and Bird Pollination in Bombax ceiba (PDF), found that mature buds open at night, releasing a somewhat rancid odour. They are bright red, held upright on the tips of strong branches, and produce copious amounts of nectar. As noted, this pollination syndrome is indicative of two pollinators: birds and bats.

Among the many visitors to the tree (including bees, squirrels, and monkeys), Raju et al. observed that only bats and birds were pollinating the flowers. Many of the other animals were found to be detrimental to the pollination process, through florivory (flower consumption). The worst offenders, as seen in a picture from the article, were monkeys who would consume the nectar and half the flower, then nonchalantly toss the flower to the ground.