Tree Flowers: May 2016: Magnolia Stellata

Magnolia's are trees with showy flowers. They're also an ancient genus of tree, with specimens found that are identifiably belonging to the magnolia family from 95 million years ago. Specific to the Magnolia genus, M. acuminata specimens dating to 20 million years ago have been found. I find flowers of magnolia to be evocative - they look so different to most other flowers, so big and beautiful. I knew I had to have one! I eventually decided on the star magnolia.

The star magnolia is closely related to the Kobushi magnolia and for a long time was considered to be a cultivar of that species. However, in 1998 it was finally accepted as a species in its own right.

I chose this tree because it grows slowly and only grows to around 2.5 metres in height and can therefore be kept reasonably happy in a container. I like that it flowers before the leaves have made an appearance and that the flower buds are protected by fuzzy bracts over winter.

Those fuzzy bracts are one of the features that gives us a clue to the magnolias ancient heritage. Most plants that have evolved more recently use sepals to protect the flower buds. The photo to the left shows different stages of development - some buds fully enclosed by the bracts, one flower just emerging from the bracts, and another with the bract falling away.

The bracts are covered with hairs to protect the flower buds from adverse weather, such as frosts. Although in severe frosts, even this adaptation can fail.

The flowers on my tree are tinged with pink before the open, but by the time they have fully opened, they are entirely white.

Another sign that magnolia trees are ancient are the strap-like tepals that resemble petals. Other ancient plants, such as water lilies also have this feature.

The flower is wide open, which presumably helped beetles to get into them - magnolias were around before bees had evolved and therefore tubes and complicated entrances would not have been beneficial.

There are many stamens and styles arranged in a spiral manner. The stamens seem oversized compared to other flowers. While many flowers have the ovary containing ovules below the flower, the magnolia seeds develop above the tepals. The carpels, which contain the ovary, of magnolias have evolved to become very tough, an advantage of this is that the beetles cannot damage them - and therefore the seeds developing within. The stamens and tepals fall away when the flower has finished.

I don't know of any other use for the star magnolia than for aesthetic reasons. Even without the flowers, the leaves start as a beautiful bronze-green before turning a lovely shade of green. The bark is smooth and grey.

There are a couple of hybrids and some cultivars, which should suit a wide variety of situations. As well as plenty of other magnolia species to suit nearly every situation.

References:

“Seeing Trees.” Goodreads. Accessed May 17, 2016. https://www.goodreads.com/work/best_book/16175762-seeing-trees-discover-the-extraordinary-secrets-of-everyday-trees.

Wikipedia. 2016. Magnolia stellata - Wikipedia, the free encyclopedia. [ONLINE] Available at: https://en.wikipedia.org/wiki/Magnolia_stellata. [Accessed 17 May 2016].
Wikipedia. 2016. Magnolia - Wikipedia, the free encyclopedia. [ONLINE] Available at: https://en.wikipedia.org/wiki/Magnolia. [Accessed 17 May 2016].