Pterocymbium tinctorium (Blanco) Merr., Publ. Bur. Sci. Gov. Lab. 27: 24 1905. (syn: Heritiera tinctoria Blanco; Pterocymbium campanulatum Pierre; Pterocymbium columnare Pierre; Pterocymbium macrocrater Warb.; Pterocymbium nicobaricum Didr.; Sterculia campanulata Wall. ex Mast.);
Assam to Malesia: Andaman Is., Assam, Borneo, Jawa, Laos, Malaya, Maluku, Myanmar, Nicobar Is., Philippines, Sulawesi, Thailand, Vietnam as per POWO;
Common name: Winged Boot Tree, Bellflower Sterculia

Trees, to 20 m high, bark grey-brown. Leaves simple, alternate; stipules ca. 6 mm long, subulate, cauducous; petiole 3-10 cm long, slender; lamina 10-15 x 7-12 cm, ovate or ovate-oblong, base cordate, apex acute or acuminate, margin entire, glabrous above, pubescent beneath, coriaceous; 5-7-ribbed from the base, palmate, prominent, intercostae scalariform. Flowers polygamous, in terminal umbellate panicles; calyx 1.5 x 4 cm, campanulate, glabrous, lobes 5, lanceolate; stamens 10 or 8, united to form a staminal column, pubescent below; ovary superior, 5, free, sessile, gibbous at base; styles short. Fruit a follicle, 5-9 x 1.8-2.5 cm, boat shaped with a pouch-like bulging at base, glabrous, membranous, 2-lobed, lower broad, round, upper linear, obtuse, glabrous, dehiscing before maturity; seed 1, 1 cm long, basal, ellipsoid to ovoid.
Flowering and fruiting: January-May
Raised in plantations
(Attributions- Dr. N Sasidharan (Dr. B P Pal Fellow), Kerala Forest Research Institute, Peechi as per India Biodiversity Portal (Pterocymbium tinctorium javanicum (R. Br.Kosterm.))

tree at Agara Lake, HSR Layout, Bengaluru: 5 images.
Date/Time- Tree 28 FEB 2021, Flowers 1 on ground 28 FEB 2021, Buds 1 MAR 2021, Leaf 16 MAR 2021, Flowers 2 on ground 17 MAR2021
Location- Place, Altitude, GPS- Agara Lake, HSR Layout, Bengaluru. 12.923 N 77.642 E
Habitat- Garden/ Urban/ Wild/ Type- Urban.
Plant Habit- Tree/ Shrub/ Climber/ Herb- Tree.
Height/Length- 6 meters.
Leaves Type/ Shape/ Size- Oval with prominent veins.  
Inflorescence Type/ Size- Bunches like grapes
Flowers Size/ Colour/ Calyx/ Bracts- Pentamers, two types (may be male and female)
Fruits Type/ Shape/ Size Seeds- If seen in future, I will report.

Is it  Sterculia villosa ? We can confirm it now after the fruits come

It looks like Pterocymbium tinctorium of Malvaceae. If yes, then this would be an addition to our database!
Flowers of India

I am attaching two more pictures. The images of Pterocymbium tinctorium in ‘Flowers of India’ are quite close to my images.

It appears to me that the image shows a female flower. The seeds are not formed yet.

Any Malvaceae member?

Need  sometime to check. Seems to be a distinctive tree not seen earlier in Mysore or Bangalore by me.

Sterculia species. S.companulata ?????

I thought it looks more like some SterculiaPterocymbium tinctorium never seen this.
I will one day go and see the tree.
Thanks for showing me new one.

I would like to add one more photo. It is showing the fruit. This photo is clicked on 23 MAR 2021.

I had been following the development of flowers on the tree at Agara Lake, namely Pterocimbium tinctorium.
I would like to share the following.
Lots of flowers were seen on the tree from 17 FEB 2022. Many of them were falling on the ground. I observed some of them but could not see even a single female flower, all were male flowers. In the first week of March, the number of flowers on the tree was greatly reduced and so the flowers falling on the ground. On 9 MAR 2022 there were few flowers on the tree. By bending one of the branches, I could reach one of the flowers. It was closed. I opened the tepals. And what a surprise, there wasn’t the usual staminal column but a gynoecium. This confirmed that it was a female flower.
I am sharing photos of the female flower.



References: POWO  Catalogue of Life  The Plant List Ver.1.1  WCSP  IPNI  GBIF (High resolution specimens) Flora of peninsular India Flowers of India  India Biodiversity Portal  Kerala plants (Pterocymbium tinctorium javanicum (R. Br.Kosterm.)  Wikipedia Wikimedia Commons  PROSEA  Useful Tropical Plants  nbrienvis pdf
Pterocymbium tinctorium (Merrill, 1901) (Magnoliophyta: Malvales: Sterculiaceae: Sterculioideae): New record from mainland India and extension of geographic distribution– June 2013 Check List 9(2)- Bikarma Singh, Dibyendu Adhikari, Saroj Barik and Arun Chettri (Abstract: We present a new record of the winged-boot tree (Pterocymbium tinctorium) discovered in the Khasi Hills of Meghalaya on the Indian mainland. With this record, the known geographical distribution of P. tinctorium is now extended up to the foothills of the Eastern Himalayas in Southeast Asia. The species was recorded from the tropical moist deciduous forests of Meghalaya. The habitat of P. tinctorium was characterized by the presence of surface lime-stone with karst topography. Future investigations should aim at identifying the factors responsible for the restricted distribution of this species so that appropriate conservation measures can be taken.)

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