Barringtonia racemosa

Common Names: Poeierkwasboom (Afrikaans), Common Putat (English), Putat Sungei (Malay), সমুন্দরফল (Bengali), จิกสวน (Thai), サガリバナ (Japanese), 玉蕊/水茄苳/穗花棋盤腳 (Chinese)
Scientific Name: Barringtonia racemosa (L.) Spreng.
Family: Lecythidaceae
Natural Distribution: South Africa (KwaZulu-Natal), Mozambique, Tanzania, Somalia, Madagascar, Seychelles, India, Sri Lanka, Andaman and Nicobar Islands, Southeast Asia, Southern China (including Hainan Island), Ryukyu Island (Southward starting from Amami Islands), Taiwan, Micronesia, Melanesia, Polynesia, Northeastern Australia
Natural Habitat: Tropical and subtropical coastal and mangrove forests
Description: Evergreen tree usually around 10m tall at most. Alternate obovate-oblong simple leaves are glossy when mature, can grow up to 35cm long and about 15cm wide, and is pointy at the tip. The red new shoots are papery, gradually growing greener glossier. Leaves crown at the tip of branches.
Flower: Axillary inflorescence in the form of pendulous raceme. In summer the plant begins to bloom attractive whitish to pale pink bisexual flowers (4 red sepals, 4 pale pink petals and lots of whitish to pale pink stamens). Peduncle can reach 80cm. The nectar attracts pollinators including moths and bats.
Seeds: Oval-shaped fruit is light brownish with creases (from the lobes of flower). The fibrous outer coating makes the seed buoyant. The single seed inside the fruit is recalcitrant (but the seed can still germinate after months in the sea).  Quite some number of fruits are seedless. Sometimes the ripe fruit stays on the tree for a long time, but most fruits mature and drop during the first few months of the year. 

This is a very widespread species. They are dispersed by water, such as the sea or river. In their natural distribution, seedlings can be found on beach shores. They can tolerate saline soils but probably grow best along freshwater rivers. 

2018/01/25, this is one of the 2 Barringtonia racemosa seeds I have planted. The medium I used was clay soil and potting mix (about 1 to 1). I left some Sphagnum moss on top just in case the top dried out. I heard that this species loves it moist so I watered it everyday.

Macadamia tetraphylla

Common Names: Macadamia Nut/Rough-Shelled Bush Nut/Queensland Nut (English), Mắc ca bốn lá (Vietnamese), 四葉澳洲堅果 (Chinese)
Scientific Name: Macadamia tetraphylla L.A.S.Johnson
Family: Proteaceae
Natural Distribution: Eastern Australian coastal rainforests in southeastern Queensland and northeastern New South Wales (near the state borders)
Natural Habitat: Coastal subtropical rainforests, subtropical montane rainforests
Conservation Status: Vulnerable due to habitat lost
Description: Small tree to around 15m tall. 4 simple stiff and highly serrated leaves around the leaf node in a whorl that can grow to 20cm long and 3-4cm wide. New leaves reddish pink and softer and hirsute while mature leaves are deep green and very rough. Mature trees are dense and grow numerous branches. It cannot tolerate frost (although many sources suggest they can survive short periods of frost, it is best to avoid it). 
Flower: Flowers usually in winter (around August in Australia). The long 15-40cm axillary clusters of flower are pinkish cream-coloured to purplish. Individual flowers are about 1cm in diameter. 
Seeds: Seeds are edible. Fruits can take 6 months to mature, usually late autumn/fall. The fruit has an outer greenish grey coat (turns brownish when mature) and inside it is the tough, brown and wrinkly (relatively) shell and the edible seed is inside the shell. Seed itself is about 2-3cm in diameter. Probably unable to be stored for future planting. 

One of the edible species of Macadamia along with Macadamia integrifolia. Both mentioned species have been successfully commercialised. Their numbers are decreasing, with minimal populations in Australia and limited number of individuals within a population, they are considerably vulnerable to extinction in their natural habitat. It takes around 5 years to mature and produce flowers. The fruits of the Macadamia genus are most likely dispersed by water (river, streams and other water bodies). Although considered a small tree in the rainforest, they can live over 100 years old. 

When looking for seeds to plant, pick the ones that have already fallen onto the ground, those are definitely mature. If none are on the ground, pick the ones with the green coating bits opened up. I was about to go on a month trip when I picked the seeds up so I put the seeds in Sphagnum moss and let it germinate. I thought it would take longer than 3 months because of the hard shell but surprisingly one germinated within a month!  The other one germinated about one month later and the other one germinated about 2-3 weeks after the last one germinated.

28th May 2018, I found out that my Macadamia had germinated already.

Peltophorum pterocarpum

Common Names: Copperwood/Yellow Flame Tree/Copper Pod (English), Jemerlang Laut (Malay), Soga (Indonesian), Lim xẹt (Vietnamese), นนทร (Thai), কনকচূড়া (Bengali), ചരക്കൊന്ന (Malayalam), 盾柱木(Chinese)
Scientific Name: Peltophorum pterocarpum (DC.) K.Heyne [1]
Family: Fabaceae/Leguminosae (Subfamily: Caesalpinioideae)
Natural Distribution: Sri Lanka, Myanmar, Thailand, Malaysia, Singapore, Indonesia, Brunei, Philippines, Vietnam, Northeastern Australia, Papua New Guinea [2]
Natural Habitat: Low elevation Tropical Forest, also found near coastal regions
Description: Evergreen tree  (probably a subcanopy tree in the natural habitat) that can grow up to around 20 metres. Leaves are compounded. Leaflets can reach 20 cm. Mature trees usually display umbrella-like tree crowns.
Flower: The tree has terminal or axillary inflorescence, with flamboyant yellow flowers around June (Summer in Northern Hemisphere).
Seeds: One mature brown pod (mature ones are woody) can contain up to two or three whitish mature seeds but usually will contain a single seed. The seed is surrounded by a hard shell of seed coat and is quite flat. The seed is said to exhibit orthodox behaviour and require scarification to speed up germination. 

This species is very shade tolerant but at the same time is sun loving. This species is perhaps the most famous out of the genus (although the genus is spread throughout the tropics around the world) and is planted throughout the tropics and subtropics (more so in Asia). This species can fix atmospheric nitrogen. The USDA zone for this species is most likely around 10. I heard that it is not too fast growing and supposedly quite drought hardy.

Peltophorum pterocarpum seed pod and seed size