Tuesday, November 27, 2007

Impatiens chinensis

It was a painfully slow 24 hrs ride from Hoi An to Dalat. I left Hoi An in the evening to arrive in Nha Trang around dawn. I caught the bus to Dalat at round 9 am traveling at 50 km/hr through rather degraded pastureland. The bus snaked up to the Dalat plateau after lunch. The montane coolness was revitalizing and refreshing; pine plantation started to appear. From the window, i caught a glimpse of delicate pink flowers near ditches or drainage channels. Unfortunately, the bus was not going to stop... However, i was lucky my guide brought me to a less frequent small waterfall the following day to see the dalat sights. Here i managed to photograph this beautiful Impatiens chinensis in situ. It was then approaching the dry season, there were no mature seed pods to be seen.

Trying to pin a name to this species drawed a blank until 2006 when a Taiwanese nurserymen identified it as I. chinensis. It was said to be common weed of Southern China in marshy areas. A websearch yields couple of photos of this species but the flowers are smaller, less symmetrical and the color is inferior. If you can confirm; or suggest another identification, would like to have your comments.

Tuesday, November 20, 2007

Impatiens from Vietnam

I was at Border's this weekend. Wasn't having any expectation of new interesting plant books on the shelf. Browsing through familiar titles i came across a new title Impatiens by Raymond Morgan (Timberpress). The author covered impatiens from Africa, Masdagascar, Indian sub-continent, Southeast Asia and China. Was very tempted to buy it but after the initial excitement... i realized that most species (with pictures) are quite well known. Christopher Grey-Wilson has devoted a monograph - Impatiens of Africa. So i am encouraged start-off with a few impatiens i saw during my travels around Southeast Asia.

I chanced upon this impatiens at Cat Ba Island, Halong Bay during my Vietnam trip in Nov 2005. This perennial balsam was found growing from peaty humus pockets on razor sharp eroded karst. It grows to around 50-80 cm tall from the base and have very pale pink or white flowers. It has a spindle-shaped basal stem up to the first side-branch. Wild plants of Halong Bay identified this as I. verrucifer. Flora of vietnam gives a distribution to include Ninhbinh, Quangnam and Phanrang on the mainland. Athough the plant is flowering vigorously, there is no developing or mature seed pods. I was not sure if November is the flowering season; maybe it is just opportunistic flowering when water is available. That year was probably an anomaly with typhoon bringing rains later and further north. October till April is normally the cool season and past typhoon season. Other plants that share a similar eco-niche are Euphorbia antiquorum, Sacrostemma sp (milk weed stem-climber), Dracaena cambodiana (Yucca-like), Drynaria sp (fern), Stephania sp (climber with peltate leaves & has a tuber).

Saturday, November 17, 2007

Mystery Crassulaceae

This plant is a real pain to identify but only those in Singapore will have this problem. Let me explain... it appears on sale infrequently, it looks like a Kalanchoe, and like kalanchoe it can be started easily from bits of stem or broken leaves, but nobody has seen the flowers. Being right on the equator, okay to be exact just 1° north of the equator, there's no short days of autumn to trigger flowering.

During my recent trip to China, i spotted a nice pot of flowering kalanchoe... but something is not right. The vegetative parts looked like the kalanchoe i know from Singapore but the flowers are wrong! The flowers showed stronger affinities to Sedum. While trying to read up on Chinese plants which i saw during the trip... i come across a photo of the above in The Garden Plants of China by Peter Valder, Timber Press naming it Sedum spectabilis. Going by a more authoritative reference it is Hylotelephium spectabile per Flora of China vol.8. It is found all the way from Eastern China to Manchuria and Korea.

So much for all the mystery... it is just a non-flowering poor specimen of a highly popular ornamental plant introduced to Europe and N. America.

Friday, November 09, 2007

Pectecilis susannae

This is a very famous orchid. It is found in the monsoon belt of Southeast Asia and into S. China, with a very distinct dry and wet season. The natural habitat is seasonal grasslands, in soil pockets amongst rocks and grass. Rumphius named it after his wife in Flora of Ambon:

in memory of her [Susanna] who when alive, was my first companion and helpmate in looking for herbs and plants, and who was also the first one to show it to me

Currently it is very rare in the wild and equally rare in cultivation. It is rare in cultivation probably because of its very specific growth/dormancy requirements and growers tend to treat it like most other orchids which require year round watering. Like H. lindleyana in the former post, after flowering this species dies down to a tuber resting for couple of months before a new shoot will emerge from the soil. At this point, watering can be resumed. It likes to be grown in sandy clay enriched with high potash & phosphate. The mix must retain moisture and must be well drained. The plant grows vigorously for 3-4 mths before flowering developing a tall stem; the stem should be supported if necessary aovid toppling over resulting in unrecoverable damage to basal stem jointed to the tuber. Watering should be slowly reduce as leaves and flowers dries up to prepare for tuber development and dormancy. Some water should still be given to soften the mix and aid tuber development. Here we go, flowers taken back in Oct this year.

A Perfect Flower

Before i left for a 2 week vacation ago, this orchid was budding and sending out a long inflorescence. It is the largest inflorescence that it ever had. Fortunately, i was able to have a friend who's an expert plant babysitter. Under tender loving care; under bright indirect light, careful watering, voila: the flowers of Habenaria lindleyana!

This is a seasonal terrestial orchid from thailand and maybe found in other neighboring countries of indochina. After flowering, the inflorescence and leaves will slowly yellow and die. Meantime watering should be reduced correspondingly. A underground tuber will form in time and if the plant is vigorous, mature and robust... with luck maybe one can get 1 large or 2 tubers. It is important that a dry rest is given; tubers can remain in the potting mix with a dribble of water weekly or twice a month. Normally, the tuber will wake up and develop a growing tip after about 3 months of dormancy not very differerent from onions left on in the kitchen. The active life cycle starts here... regular watering, feeding and pest control etc. Light regular feeding with higher P, K is important to ensure vigorous and active growth. Interestingly, i find that this habenaria enjoys a sandy clay mix which retains moisture.