Carex phacota

Carex phacota is one of the 20-odd Carex species (Cyperaceae) in Hong Kong. It was assessed to be very rare without recent specimens. However several localities have been found recently because of more nature lovers getting interest in the diversity of local flora.

Chlorophytum laxum

Chlorophytum laxum (Liliaceae) is an inconspicuous herbaceous species found in grassland or forest edge in Hong Kong. It was listed as having restricted distribution in Hong Kong. Fruits are remarkable as the capsules are acutely three-angled.

Manglietia cf. yuyuanensis

In a hiking trip in late June 2010, an atypical Manglietia species was found in a montane valley. We quickly recognized that it was not Manglietia fordiana, the only Manglietia species recorded in Hong Kong, as it has much smaller flowers than M. fordiana. It was thought to be another "taxon" no matter what taxonomic difference it refers to.

Magnoliaceae is indeed very well documented in China as they have very high ornamental and cultural value in the country. In the book "Magnolias of China", several small-flowered Manglietia were identified but the species matches only one of them, Manglietia yuyuanensis, which also has a geographic range close to Hong Kong. However, different taxonomists have different opinions on whether Manglietia yuyuanensis should be included in Manglietia fordiana. However, besides the morphological difference, we also noticed there is a difference of their flowering time which makes natural inter-breeding very unlikely to happen. Possibility of natural inter-breeding is conventionally an important criteria in taxonomy so this supports that they are at least of subspecies or variety level difference rather than a simple inclusion.

Yesterday we managed to make another trip to the valley to search for fruits but none was found. However, it is still exciting as more individuals were found. Many of them were adult tree but sapling or seedling were absent, suggesting that its regeneration is poor.

Balanophora fungosa

Genus Balanophora is belonging to angiosperms (flowering plants) though it is always misidentified as some kinds of fungi by hikers. Though it resembles fungi by appearance but you could find floral structures in Balanophora such as its staminate and pistillate flowers and bracts by close observation. Also, fungi is saprophytic while Balanophora is obligate parasitic with specific hosts.

The specimen shown here is Balanophora fungosa taken in Queensland in late Oct, 2010. It actually has a wide distribution which is ranged from Northeastern Australia, Pacific Islands, East Malaysia, India, Taiwan and South Japan. It was reported having various hosts including Macaranga tanarius and Diospyros philippensis etc (Hsiao et al., 2010). It has monoecious inflorescence where pistillate flowers are on the upper part of the inflorescence while staminate flowers are on the lower part. There is also a wide range of floral color where the populations from Taiwan and Japan are pinkish orange while those in Queensland are yellow, as shown in the photographs here. Though it is considered as rare and vulnerable in Taiwan but it was found very abundant on the forest ground in Queensland, maybe due to different climate and host availability.


Reference:
Hsiao, S., W. Huang and L. Maw-Sun (2010). Genetic diversity of Balanophora fungosa and its conservation in Taiwan. Botanical Studies 51: 217-222.

Early Morning anthesis

Flowers of Thysanotus chinensis (Liliaceae) open fully between around 7 am and 9 am. It was listed as rare in previous biodiversity survey.

Early morning anthesis is a common phenomenon scattered through angiosperms. Flowers of the early morning anthesis species open in early morning, probably soon after dawn and close before or around mid-day. It is suggested to prevent heat stress as anther and stigma would be destroyed by over-heating and closure of flowers would also reduce transpiration. These are reasonable explainations as most of the early morning anthesis species are herbaceous, grassland inhabitants.

It is important to note that early morning anthesis should be more related to the pollinator activity where it is the ultimate goal of floral anthesis. After a quick search on the literatures, bees were reported to be the major pollinators of early morning anthesis species including Pyrrhopappus carolinianus (Asteraceae) (Estes and Thorp, 1975) and Cassia fasciculata (Caesalpiniaceae) (Thorp and Estes, 1975). Bees were reported to forage actively for the pollen after dawn and their activities quickly reduced towards the mid-day. The close relationship between pollinator activity and timing of anthesis is interesting and I think the early morning thesis species in Hong Kong are also pollinated by bees as certain groups of them are particularly active in the morning. There is a number of candidates for observation including the ones shown here, namely Geissapis cristata (Fabaceae), Thysanotus chinensis (Liliaceae) and Xyris pauciflora (Xyridaceae).

Geissapis cristata (Fabaceae) is another rare species in Hong Kong which inhabits lowland wetland.

Xyris pauciflora (Xyridaceae) is commonly found near wet places in Hong Kong. All of the species listed here are having brightly-colored corolla. It is an important feature to send visual signal to pollinators and to offer them a landing place.

References:

Estes J.R. and Thorp R.W. (1975) Pollination Ecology of Pyrrhopappus carolinianus (Compositae). American Journal of Botany 62: 148-159.

Thorp R.W. and Estes J.R. (1975) Intrafloral behavior of bees on flowers of Cassia fasciculata. Journal of the Kansas Entomological Society 48: 175-184.

Anisopappus chinensis

Anisopappus chinensis (Asteraceae) is a Chinese endemic which is mainly ranged from South China. It is also the only species from the genus distributed in China. It has a prolonged flowering season where flowers were seen from April to October. It explicitly inhabits dry grassy slope in Hong Kong. Though it is said to be a common species, I only had a few encounter of it. However, hiking on dry grassy slope in high summer is something not very pleasant.

Eleocharis geniculata

Eleocharis (Cyperaceae) is a large genus comprised of about 200 species. Most of them are widely distributed in the tropical and subtropical regions over the world. Their very broad geographical range might probably attribute to wind-pollination and wind-dispersal mechanisms, which are particularly efficient in open and windy habitats that most of the members inhabit. No leaf blade can be found in the genus where only shealth is present which is a major characteristic for the genus.

Eleocharis geniculata is uncommon in Hong Kong. Their abundance might be confined by limited suitable habitat which mainly inhabit coastal wetlands. Identification of it is easy by identifying three major characters:

1. Spickelets are broader than culm (shown in 1st photo);
2. Stigma is bifid (shown in 3rd photo);
3. Nuts are blackish, of about 1 mm long with 6-8 hypogynous bristles (shown in 3rd photo).

Scleria lithosperma [misidentified as Scleria biflora]

The above specimen is more likely Scleria lithosperma than S. biflora. After checking a bunch of literatures I found that nuts of S. biflora should be globose, regularly cancellate and beaked with black/purplish persistent style base. It is obviously wrong for the above specimen which is having obtusely trigonous, smooth and shining nuts. Both species could have simple inflorescence which is originally thought not the case for S. lithosperma.

I here keep the original message of S. biflora. However its status might not be correct:

Scleria biflora (Cyperaceae) is most likely the smallest Scleria species in Hong Kong. Inflorescence only bears one or two florets which gives its scientific name biflora. It is quite common in Hong Kong which can mainly be found in forest edge, shrubland or path side. However, the inflorescence or nuts are too inconspicuous which might usually be overlooked. It is also difficult to photograph where the above pictures are heavily cropped in order to show its inflorescence and nuts.

Fimbristylis cymosa

Fimbristylis cymosa (Cyperaceae) is one of the commonest Fimbristylis species seen in Hong Kong especially in the coastal or sandy shores. The height of the plant can be varied quite much which is ranged from about 10 to 40 cm. It has a compound inflorescence with relatively small spickelets. I roughly measured over 10 spickelets from several individuals and most of them are about 3 mm. One of the easiest way to distinguish this species from many other Fimbristylis is that it produces blackish nuts which gives its Chinese name "黑果飄拂草" (literally means black-nut Fimbristylis). Though some publications stated that its stigma is either bifid or trifid, so far I could only find the bifid one but none of them are trifid. I will correct myself if I did find the latter.

Rhynchospora corymbosa

Rhynchospora corymbosa (Cyperaceae) is a globally distributed species which is reported to be found in tropical and subtropical regions. However it was previously assessed as rare in Hong Kong which can only be found in a few localities. The above individual was found in an undescribed locality which is only holding a few individuals. It mainly inhabits lowland wetland or streamside which is, therefore, very vulnerable to disturbance, channelization, development and pollution. There is indeed quite a lot of wetland-associated species in Hong Kong so it's important to take care of this habitat in order to conserve this diversity.

Fimbristylis thomsonii

Fimbristylis thomsonii (Cyperaceae) is a very common sedge in grassland or hillside in Hong Kong. There are several features making it recognizable in the field: conical spickelets where scales are spirally arranged; leaf-like bracts; many spickelets (usually more than 2); and 3 stigmas on a single style which could be visible when it is in stigma receptive phase. Habitat is also a very important clue to rule out those coastal species in the long species list.

It has quite a long flowering season which has been recorded to flower since April and I could still find many blooming ones at the end of August.

Firmiana simplex

Status of Firmiana simplex (Sterculiaceae) in Hong Kong is interesting. F. simplex is a very famous Chinese tree which is commonly cultivated in most parts of China where it is also originated from. However, most of the official literatures suggest wild populations of F. simplex in Hong Kong appear to be naturalized from cultivated individuals but not truly wild. Personally I am not convinced very much by this as many individuals are found far away from the hiking paths or main roads but in the valley. There is not many exotic woody species could invade into a new environment as successful as this. Also, wild populations of F. simplex are mainly concentrated to the Eastern part of Hong Kong but not the central and western regions. All these evidences seem not a natural consequence of naturalization of cultivated species but more likely to be true wild populations. Podocarpus macrophyllus shows a similar distribution in Hong Kong. Is this kind of biased distribution because of the oceanic micro-climate from the Eastern side of Hong Kong?

Firmiana simplex resembles Vernicia montana quite much if flower or fruit is not available. They are actually belonging to different family. The former is from Sterculiaceae while the latter is Euphorbiaceae. Glands are often present at the leaf base in Euphorbiaceae but lacked in Sterculiaceae. From the above picture, glands are absent at the leaf base which is a very useful clue to rule V. montana out. Also, F. simplex is sometimes called 青桐 (literally means tree with greenish bark). Picture below shows a very typical appearance of the bark of F. simplex.

Streblus taxoides

Streblus, a very unfamiliar genus to me, belongs to Moraceae where about five species could be found in Hainan but none in Hong Kong. I only managed to find immature fruits of S. taxoides during my visit to Hainan in late May. Moraceae usually produces syncarp like Ficus or Artocarpus but some of the genera also produces drupe like Streblus.

Syzygium impressum

Syzygium impressum (Myrtaceae) is a very recently described species which is only valid since 2008. Botanists from IBSC found some questionable specimens of Syzygium buxifolium which consistently differed from the typical one when they were preparing the Flora of Hong Kong. All of those specimens were collected from the Sunset Peak, Hong Kong. This taxon resembles S. buxifolium very much, but could be distinguished by its ovate leaves, impressed midveins and smaller fruits. It was later named as Syzygium impressum which was derived from its conspicuously impressed midveins.

There are nine Syzygium species in Hong Kong whereas identification based on vegetative parts is sometimes difficult. However, not many species have angled young branchlets where S. impressum is one of them (see below):

In addition, by careful assessment and observation, the midveins of it are conspicuously impressed adaxially.

The general apperance of it is indeed like small-leave Ilex species as its crown is very dense. Also, there isn't major habitat overlapping between it and S. buxifolium as the former is solely recorded from streamsides in montane forests but the latter is a very common shrub in lowland forest edge and shrubland.

The recent encounter reminds me that I had seen a very similar one apart from Sunset Peak. Unfortunately I didn't take any specimen or photographs at that time and there is no way to verify unless re-visiting the site. However, woody species is comparatively having lower chance to cause endemism especially in such a tiny place. It is not unexpected to find more populations of this currently-restricted species in other parts of Hong Kong, or even Guangdong. It might probably be overlooked in the past which was confused with S. buxifolium or its allied taxa.

Syzygium fluviatile

There is very few information and pictures of Syzygium fluviatile (Myrtaceae) available on internet and books after some intensive search. It might be because of its globally narrow distribution as it is probably a Chinese endemic. Even so, it is only found in three provinces in China, including Guangxi, Guizhou and Hainan according to Flora of China. However, a rapid biodiversity survey report prepared by KFBG, Hong Kong, stated that this species is endemic to Hainan. Indeed, it is a very common streamside shrub in Hainan based on my own observation. The specific epithet "fluviatile" means existing in or about rivers which is very true.

Scutellaria javanica

Scutellaria javanica is a large Scutellaria species which could reach up to 1 m tall and has relative large flowers among other Scutellaria species. In China, it is only distributed in Hainan which is a nationally uncommon species. It can also be found in Indonesia and Philippines, suggesting it is a tropical species. Its type specimen was from Java which gives its specific name, javanica.

S. javanica is believed to be fairly common in Hainan which is mainly found near water or along streams. It is remarkably easy to identify by its large individual and dark purple flowers.

Canthium horridum

Canthium horridum is a common weedy shrub in Hainan Island but a rare species in Hong Kong. Rubiaceae is a tropical family which is very diverse and predominant in Asian tropical regions. Identifying Rubiaceae is not difficult in field by its opposite leaves, persistent stipules and lack of latex. Some of its members are armed with thorns though it is quite uncommon.

Hydnocarpus hainanensis

Hydnocarpus hainensis is a restrictedly distributed species in Southeast Asia which is ranged from southern China to Vietnam. The Chinese population is mostly restricted in Hainan Island. It is listed as vulnerable according to the IUCN Redlist though its status might be outdated. However, as it is mainly found in low altitude in mountaneous regions where deforestation is serious, it still constitutes certain level of conservation importance.

Based on the on-site observation, flowers emit some unpleasant smell like spoiling food. Flowers in anthesis are very easy to detach where mass dropping of flowers occur in strong wind.