Tuesday, January 19, 2016

Plant of the day is: Delonix regia or flamboyant

Plant of the day is: Delonix regia or flamboyant


A decidedly bright and chipper plant on these dark days of winter.  I'm a little enthralled with how large the cotyledons are as they emerge.  Truly an elegant seed as it germinates, gracefully arching.  Perhaps I'll try to snag a photo tomorrow to really show it.  How quickly will the cotyledons push up and expand?  What will they look like tomorrow?  These questions get my boots on in the morning.

Pretty much sums up my excitement.  Just look at that.  Beautiful.

Taxonomy, etc.:  I promise I don't have a thing for legumes.  Or maybe I do.  I probably do.  One thing I enjoy about them is their relative ease of germination (see below).  There are a lot of vivid colors and floriferous species in the family. with brilliant reds, yellows, purples, and everything in between.  Genus published by the famous William Hooker who was Regius Professor of Botany at Glasgow University and Director of the Royal Botanic Gardens Kew.  He was good friends with Sir Joseph Banks (James Cook!!) and his son Joseph Hooker later succeeded him as Director of Kew.  
Side note: Also have two species of Banksia germinating, which were named after Joseph Banks.  Really enjoying digging into the history of all these botanists a bit more, it helps paint the bigger picture I think.  D. regia is sometimes called the royal Poinciana ...which actually relates to the former genus that Delonix was in...so we should stop calling it that right?  It's a pretty small genus of only about 11 accepted species all native to Madagascar or east Africa.  The majority of them in Madagascar so a few are endangered or critically endangered.  D. tomentosa is only known from the one type specimen collected over 100 years ago.  It has not been seen since and is likely extinct. :(.  D. velutina and D. pumila are also endangered.  Other members have held up fairly well against the deforestation of the island but are becoming more scattered by the day.

Photo Credit: Marc Averette CC BY-SA 3.0

Description:  Fun fact.  It was widely cultivated for some time before anyone knew where it actually came from until it was discovered growing in the wild in Madagascar in the 1930s.  Nifty.  Often considered one of the worlds most colorful trees.  I agrees.  D. regia is a tree typically reading 9 to 12 m with an arching umbrella-like canopy that can actually be wider than the tree is tall, a beautiful trait.  It is actually deciduous in climates with dry seasons but semi-evergreen in wetter year round climates.  Leaves are a nice feature and are alternate, light green, and feathery with opposite leaflets lacking stalks.  Leaves are minutely hairy on both sides.  At the base of the petiole are 2 compressed stipules with long, narrow, comblike teeth.  Now I'm getting excited to see the first true leaves (yay).  Flowers are obviously red in loosely arranged corymbs.  Flowers have 4 petals, typically red (though there is an orange cultivar...ouuuu), with whitish insides with red spots and streaks.  Fruit is your typically legume pod and seeds are very narrow almost elliptical.  I remember thinking the seeds felt and looked a little odd for a legume and I wondered how viable they were.  They were.  Anyways, it takes about 4 to 5 years to reach maturity (point in which it can flower).  A great description can be found at the worldagroforestry.org site.  Thought to be pollinated by sunbirds but more pollinator research would definitely help confirm this.  


Habitat/culture:  A tough and drought tolerant plant.  Likes sandy soils.  Found in the western dry forests of Madagascar.  While it is widespread throughout the world, and naturalized in Florida, Hawaii, and invasive in Australia, its native habitat is growing more fragmented by slash-and-burn agriculture, charcoal production, grazing, and bush fires.   Requires a lot of sun and, for best flowering should be grown a little on the dry side.  It does have some widespread roots that can damage pavement so maybe not the best street tree.  Like many plants of that area and southern Africa, it appreciates a dry period in the winter time.  Oh, definitely tropical, non hardy.  Better have a warm sunny spot and a lot of room if you want to try it indoors.  

Propagation:   Most members typically really on a physical dormancy in the form of a hard seed coat to delay dormancy, rather than underdeveloped embryos or inhibiting hormones (typically abscisic acid).  This physical dormancy can be overcome by nicking with a file (or toenail clippers...I'm telling ya, they're amazing), dipping in a strong acid (sulfuric), OR dipping in boiling water or soaking in near boiling water initially and then allowing to soak overnight in same water after it cools.  There are other methods of course, but those are the highlights.  I've been using the boiling method of late and I think it's a good method.  I either dip in boiling water for 5 seconds or do the aforementioned overnight soak.  I feel like there is a lower likelihood of damaging the seed by nicking or filing too deeply.  If there is still some dormancy left...I figure it'll just take longer to imbibe and germinate.  You can typically see if the seed has swollen up or imbibed, which is an indicator that you have punched through that seed coat.  If you didn't, you can always wait longer, the nice thing about a hard seed coat like that is that it is very difficult for pathogens to rot out.


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