Saturday, November 29, 2008

Asarum hongkongense

Genus Asarum L. (Aristolochiaceae)
contains about 90 species, mainly distributed in SE Asia. 39 species occur in China in which one is endemic to Hong Kong - Asarum hongkongense, a critically endangered species.

Flowers of Asarum are close to the ground and have strange shape. It is commonly believed that flowers of Asarum are pollinated by insects due to the traits of the flowers like the calyx surface ornamentation, tiny glands on the inner calyx surface and caudate sepal lobe extensions. Unlike most flowers of Aristolochia, flowers of Asarum give no bad odor which suggests Asarum is not imitating animal corpse that attract flies to pollinate. An old study suggested that the flowers resemble mushrooms that attract fungal gnats to lay eggs inside the flowers which may pollinate the flowers. However, more recent studies demonstrate that Asarum produces autogamous flowers which undergo self-pollination. The putative insect-attracting floral characters are therefore primitive which maybe derived from an insect-pollinating ancestor.

Flowers of Asarum are protogynous. The stigmas are receptive at the beginning of anthesis while anthers lie horizontally at the bottom of the flowers so that stigmas and anthers are spatially separated. In the later stages of the anthesis, the stamen filaments become erect (See the second picture) and the anthers dehisced to release pollen grains which promote intrafloral pollination. However, no detailed phenological study has been carried out for A. hongkongense so far, it is still not sure if its pollination mechanism is like such case.

Monday, November 24, 2008

Odorrana livida

Genus Odorrana is belonging to the family Ranidae which is comprised of 21 described species. Most of them occur in China where 16 can be found while the other 5 are in Japan. Odorrana livida is the most widespread species which is widely distributed in South-east Asia including India, China and Malaysia.

Recent study shows that Odorrana is most probably origniated at Mt. Hengduan and Plateau of western Yunnan where is the center of diversification of most fauna and flora. Odorrana is shown dispersing from the west to the east. Odorrana species occurring in the Southeast China, including O. livida, are more advanced within the genus.

Saturday, November 22, 2008

Sarcococca longipetiolata

Genus Sarcococca (Buxaceae)
A small genus comprises of about 20 species mainly distributed in Asia. 9 species can be found in China while 5 of them are endemic to China. S. longipetiolata is one of the endemic species which is narrowly distributed in Hong Kong, N. Guangdong and S. Hunan.

S. longipetiolata is a very rare species in Hong Kong that is restricted to Mount Parker on Hong Kong Island. It is therefore very susceptible to human disturbance or urban development.

It has no urgent need for conservation measure as it is located in the country park area where all wild plant species are protected by laws. However, visiting this rare species becomes a gimmick of some local eco-tours. Disclosure of the location of the species to the public might bring some unpreditable influence to it.

Sunday, November 16, 2008

Red-billed Starling (Sturnus sericeus)

Troops of Red-billed Starling flying around with loud noise are commonly seen in the winter in Hong Kong. They are believed to be winter visitors including passage migrants whose number reaches the peak during the first two weeks of November.

Pay attention if there is any other starlings mixing with the large flocks!

Wednesday, November 12, 2008

Impatiens hongkongensis

Genus Impatiens L. (Balsaminaceae)
The largest genus in Balsaminaceae which produces spectacular flowers. It comprises of over 900 species all over the world and ranges from India to South-east Asia. 240 has been found in China where most of them are distributed in the south-western part of China.

Impatiens hongkongensis is mostly found in wet places by streams and in ravines. It produces pale yellow flowers which may attract people to collect them from the wild for ornamental uses. It is thus protected under Forestry Regulations and listed in Rare and Precious Plants of Hong Kong.

Flowers of I. hongkongensis are probably protandrous (Presentation of pollens come befores stigma becoming active) to prevent self-pollination. Bombus species (Bumble-bees) and hawk moths are most likely to be the pollinators. However, detailed pollination ecology of the plant has not been studied. Too little is known so far for this narrowly distributed species.

Monday, November 10, 2008

Vespa discolor

Genus Vespa, also known as hornets, contains 22 species all over the world and eight (V. mandarinia is newly discovered) can be found in Hong Kong so far. They will construct their own colony comprises of a queen, males and workers. The nesting sites vary from one species to another and also intraspecifically.

Vespa discolor
is one of the most common hornets in Hong Kong. This species is un-aggresive and will not attempt to attack deliberately unless too much disturbance is caused to their nests. It is a generalist hunter and scavenger which prey on any kind of insects which they are able to kill (A wandering glider Pantala flavescens is killed in the picture). The nesting period of V. discolor is quite long which reaches 9 months from colony initiation to disintegration.

Eria sinica

Genus Eria Lindl. (Orchidaceae)
About 370 described species under the genus and they are mainly distributed in tropical Asia and Australia. 43 species are in China including 6 in Hong Kong.

Eria sinica is one of the smallest orchids found in Hong Kong while the whole individual shown in the picture is just about 1 cm height. It is apparently very similar to another native orchid Eria pusilla. These two species were mixed up before due to their great similarity in Hong Kong. They are sometimes found to grow together on steep sides of boulders together with mosses. It's very difficult to spot them even when they are flowering.

Eria sinica has a narrow distribution where it is only found in or near Hong Kong and Hainan province. The type specimen is also collected from Hong Kong. Eria sinica and all other wild orchids are protected under Forestry regulations in Hong Kong. I do think that everyone should not harvest and take the wild orchids. Everyone should has the rights to appreciate the orchids and other rare plants in the wild. Orchids blooming in the wild are always the most spectacular BUT not at the garden!

Sunday, November 9, 2008

Creobroter gemmata

It is recently reported that a mantid (identified as Creobroter gemmata) was seen jumping into a stream and a horsehair worm emerged through its anus in Hong Kong. Mantids are the common hosts of horsehair worm (Nematomorpha) in tropical and subtropical regions worldwide.

The horsehair worms copulate in its free-living stage and produce aquatic larvae. They are then actively ingested by other insects with aquatic larvae such as mosquitoe. They serve as vectors between the aquatic and terrestrial environment. The horsehair larvae continue their development if the insects are captured and eaten by mantids which are the final hosts of the worms. The worms then grow inside the mantids' abdomen and get maturity. They will then influence the hosts to approach water and emerge from the hosts. The factor influencing the hosts are still not understood.

Friday, November 7, 2008

Crested Mynah (Acridotheres cristatellus)

Crested Mynah is distributed through central and southern China and it is a common resident occurring throughout Hong Kong. It mainly inhabits agricultural areas, around fish ponds, villages and urban areas.

Local birdwatchers have seen that Crested Mynah attempted to kleptoparasitise Chinese Pond Heron deliberately. (This is a common breeding habit of cuckoos)

It is very social which are typically seen in flocks. The highest count of the aggregation recorded in Hong Kong was 600 at Chek Lap Kok on 7th Oct 07 according to "The Avifauna of Hong Kong".

Tuesday, November 4, 2008

Sonerila cantonensis

Genus Sonerila Roxb. (Melastomataceae)
Contains about 170 species distributed in tropical Asia. 12 are in the mainland where only one species are found in Hong Kong.

Though this species is described to be found in montane forest according to Flora of China, it is found at about 250 m a.s.l. in Hong Kong.

Tuesday, September 16, 2008

Commelina communis

Genus Commelina Linn. (Commelinaceae)
About 100 species distributed all over the world where the majority is found in tropical and subtropical region. 7 species are distributed in China while 5 are in Hong Kong.

Commelina communis is the most widespread species in China within the genus.

Saturday, August 23, 2008

Arisaema cordatum

Genus Arisaema Mart. (Araceae)
ca. 150 spp. distributed mainly in the tropical, subtropical and temperate region in Asia. About 82 spp. can be found in China in which 59 spp. are endemic to China. Most of the Arisaema is found in Yunnan province where 40 spp. are in Yunnan. 4 species are distributed in Hong Kong.

Arisaema has an unique and interesting inflorescence which is like a pitfall-trap system. Arisaema always form a spathe tube and a spadix appendage which probably attracts the pollinators. Pollinators landing on the apadix appendage slide to the bottom of the tube because ablative wax cover both the inner surface of the tube and the surface of the apadix appendage. Pollinators entering male flower are able to escape from the tube at the hole located at the bottom of the spathe tube while pollinators (maybe carrying pollen grains) entering female flower are trapped as no hole is formed at the bottom of the tube. They walk around to find an exit, while depositing pollen grains on the stigma.

Arisaema cordatum is endemic to China and can only be found in Guangdong and Guangxi provinces. It is narrowly distributed in Hong Kong where only two localities, Tai Mo Shan and Sunset Peak, are reported.

Monday, August 11, 2008

Marsdenia lachnostoma

Genus Marsdenia R. Br. (Asclepiadaceae)
ca. 100 spp. distributed in the tropical regions in America, Africa and Asia. 22 spp. are distributed in China while only 1 species, Marsdenia lachnostoma, is found in Hong Kong. Marsdenia are mostly climbers where shrubs or subshrubs are rare.

Marsdenia lachnostoma is a rare species in China and Hong Kong. Its range is so narrow that it is only distributed in Hong Kong within China (It is also found in Cambodia, Laos and Tailand). Because of this, it is listed in the rare and precious plants of Hong Kong and catergorized as critically endangered in the China Red Plant Data Book. Furthermore, it is still not a common species in Hong Kong while it can only be found in a few localities such as Ma On Shan, Tung Lung Chau and High Junk Peak.

The common name of M. lachnostoma is called Hairy-throat Condorvine. It is because the throat of its flowers is covered by a very dense tuft of woolly hairs.

Wednesday, July 30, 2008

Cleome rutidosperma

Genus Cleome (Capparaceae)
ca. 170 described spp. mainly distributed throughout the tropical and temperate regions. 6 spp. are found in China while most of them are exotic. Only 1 native Cleome species in Hong Kong which is C. viscosa.

Cleome is traditionally belonged to the family Capparaceae. Some recent studies suggested to include Capparaceae into Brassicaceae while some suggested to seperate Cleome to its own family Cleomaceae. Phylogeny of Capparaceae and Brassicaceae is still a hot topic for taxonomists.

Cleome rutidosperma is originated from west tropical Africa and now a common weed spreading in SE Asia, Sumatra and Java. It is a lowland ruderal (A plant growing in waste places) which can be found in the margin of farmlands in Hong Kong. It is a minor weed so far which does not affect agricultural practices.

In Sumatra, people is used to mix the seed of C. rutidosperma with tobacco to enhance it and squeezed juice of leaves is used as eye drop. Young leaves are also edible while they are boiled as food in the past.

Tuesday, July 29, 2008

Passiflora foetida

Genus Passiflora (Passifloraceae)
ca. 350 spp. mainly distributed in tropical and subtropical America, rarely in Asia and Australia. 19 spp. in China and 2 spp. in Hong Kong.

"foetida" in Passiflora foetida means that the plant is fetid where some gardeners complain about it but some also reported that no odor is noted.

Passiflora foetida is a perennial herbaceous vine, as most of Passiflora species do, that originates from tropical America, but is now a pantropic weed. It is a common weed in many places of the Pacific and Atlantic, where it favors wet areas but also tolerates arid condition. It climbs over low vegetation on roadsides and in other disturbed places. It is now listed in the Global Invasive Species Database due to its invasive nature. Monitoring and management of this toxic plant (Some parts of the plants are toxic if ingested) is recommended in tropical areas where it is present.

It is widely cultivated in the world for medicinal and culinary purposes. The fruits are edible which has a sweet taste. They are readily eaten and dispersed by birds.

Monday, July 21, 2008

Bischofia polycarpa

Genus Bischofia Bl. (Euphorbiaceae)
Consisted of only 2 species distributed from India and Sri Lanka to Indonesia, Australia and Polynesia. Both B. polycarpa and B. javanica occur in China and cultivated in Hong Kong. It is an isolated genus in Euphorbiaceae without any morphologically similar neighbors.

It is commonly believed that simpler structure and development of reproductive organs in seed plants are an indication of evolutionary advancement. A Recent study suggested that B. javanica is more primitive than B. polycarpa because the former has a more complicated inflorescence.

B. polycarpa is not native to Hong Kong while the closest locality is in N. Guangdong. It is a good street tree as it is photophilous, thermophilous, drought-tolerate and resistant to wind. It is an economic timber tree for furnitures and other decorative materials. The fruits are also very attractive to birds.

Saturday, July 19, 2008

Platysternon megacephalum

Platysternon megacephalum (Plastysternidae), also known as Big-headed turtle, is a medium-sized terrapin distributed in SE Asia. It mainly inhabits hill and mountain streams with fast-flowing water. It is good at climbing using its strong claws and long, tough tail. It is primarily nocturnal but can also be found during daytime on rainy days.

Big-headed turtle is carnivorous which presumably feeds on fish, frogs and invertebrates that can be found in the streams. Breeding habits in the wild are largely unknown although it is a very well-known pet species worldwide.

It is originally a common species in South East Asia including South China and Hong Kong. But it is heavily caught and sold in the pet and food markets recently which are the major threats to the species. It has been listed as endangered in the IUCN redlist since 2000. The localities of the species should be enclosed in order to cease the harvesting of the wild individuals.

Friday, July 18, 2008

Kaloula pulchra pulchra

Asian Painted Frog, Kaloula pulchra pulchra, is a common species ranged from much of South East Asia including Hong Kong. It is quite adaptable which is able to colonise the urban area and agricultural fields successfully while it is presumably originally a wetland/riverbank/forest edge species. It breeds in seasonal rain pools or ponds.

Asian Painted Frog acts like an ambush predator preying mainly on insects. It is able to expand itself when threatened and to secrete toxic substances from its body surface. It is also a tough species which survives in dry condition by burying itself in the ground and waiting for rain.

It is collected for consumption and pet trade (You can easily find a lot of caresheets for this speces in the internet) in many places in South East Asia but the threats to the species are not serious at this moment. It is listed as least concern in the 2007 IUCN redlist.

Thursday, July 17, 2008

Gardenia jasminoides var. jasminoides

Genus Gardenia Ellis (Rubiaceae)
ca. 250 species distributed in the tropics and subtropics; 5 spp. and 1 variety in China including 1 native sp. in Hong Kong.

Gardenia jasminoides is widely cultivated in the tropics and subtropics due to its ornamental and commercial uses. One of its uses is that the pulp of the fruits is used for coloring food yellow such as boiled beans, fish eggs, hot cakes, ices and noodles etc. Several parts of G. jasminoides are also used medicinally including roots, leaves and fruits.

It is a common and beautiful plant species in Hong Kong flowering from March to August.

Wednesday, July 16, 2008

Sphenomorphus indicus

Sphenomorphus indicus and S. incognitus both occur in Hong Kong. They are very similar in appearance that S. incognitus collected in the past had been misidentified as S. indicus. There is only one clear-cut difference between the two species which is the presence of a patch of enlarged scales at the back of the thigh in S. incognitus. It seems that there is some different in habitat preference while S. incognitus prefers waterside but S. indicus is often encountered along forest paths.

S. indicus is distributed widely in South-east Asia including S. China, Bhutan, Taiwan, Thailand, Vietnam, India and west Malaysia.

Tuesday, July 15, 2008

Ferruginous Flycatcher (Muscicapa ferruginea)

Genus Muscicapa (Muscicapidae) is a kind of old world flycatchers consisting about 25 spp. They are widespread along Europe, Africa and Asia. Most of them are migratory and they mostly prefer forest and woodland habitats. Muscicapa flycatchers mainly feed on flying insects which are caught by sallying out from an exposed perch. Other Muscicapa flycatchers occuring in Hong Kong include Asian Brown Flycatcher, Grey-streaked Flycatcher, Dark-sided Flycatcher and Brown-breasted Flycatcher.

Ferruginous flycatcher (Muscicapa ferruginea) is a monotypic species which breeds from the Himalayas east to central and western China and Taiwan. It winters in Sumatra and the Philippines.

A scarce spring migrant with only a few autumn records in Hong Kong.

Monday, July 14, 2008

Camellia crapnelliana

Genus Camellia L. (Theaceae)
An economically important genus providing valuable seed oil, tea and medicine. ca. 120 described species where most of them are in China (98 species including 13 spp. and 1 variety in Hong Kong).

Camellia crapnelliana was first collected from Mount Parker and described by W. J. Tutcher in 1903 (i.e. 克氏茶 in chinese). All Camellia species in Hong Kong are protected under Forestry Regulations Cap. 96A. C. crapnelliana is particularly rare which has also been listed as Vulnerable under IUCN red list and Rare and Precious Plants of Hong Kong.

The extracted seed oil is edible. It was introduced to Japan in 1968 but only a small number of plants have been cultivated because grafting on C.japonica or C.sasanqua is difficult.

Aster panduratus

Genus Aster L. (Asteraceae)
A large genus but taxonomically unclear. The number of the species under Aster varies depending on different approaches, ranged from 250 to 1000. They are mainly distributed in Asia, Europe and North America; ca. 100 spp. in China including 5 in Hong Kong.

Asteraceae is the second largest family in the Division Magnoliophyta (Angiosperms), with over 20,000 described species. (The largest is Orchidaceae, with about 25,000 described species).
The "flower" of Asteraceae is actually an inflorescence (Capitulum), consisting two types of florets: ray and disc florets. The petals of ray florets attract the pollinators and provide landing platform to them.

Friday, July 11, 2008

Uvaria macrophylla

Genus Uvaria L. (Annonaceae)
ca. 150 species distributed in the paleotropical region, i.e. Asia, Africa and North Australia;
10 native species in China including 4 in Hong Kong.

Flowers of U. macrophylla are protogynous (Bisexual but time sequence of presentation of pollen and stigma is seperated) which is a typical feature of Annonaceous flowers.
Smell fruity when matured.
A lovely colorful flower blooming in the summer!

Thursday, July 10, 2008

Lagerstroemia speciosa

Genus Lagerstroemia L. (Lythraceae)
ca. 55 species distributed in the tropical and subtropical region in Asia and Atlantic;
16 native species in China; 4 spp. (3 cultivated) in Hong Kong.

Lagerstroemia speciosa is a common ornamental tree in Guangdong, Guangxi and Fujian including Hong Kong. The seeds are very attractive to a local resident bird species, Grey-capped Greenfinch (Carduelis sinica).

Rubus reflexus

Genus Rubus L. (Rosaceae)
A big genus, ca. 700 species in the world (208 in China including 8 in Hong Kong);
Especially abundant in the north temperate zone while some of them are in the tropics and southern hemisphere.

Aggregate fruit berry-like. Most are edible. A lot of Rubus spp. are cultivated for commercial use in the Europe and America.