Portulaca pilosa（毛馬齒莧 ● Shaggy Purslane）

Portulaca pilosa is a herbaceous plant occasionally found near seashores in Hong Kong. According to Flora of Hong Kong, the species are found in sandy places near by the sea. P. pilosa is featured by its terete leaves and clusters of long hairs in axils of leaves. These characteristics are very likely adaptations to survive in a dry environment. The clusters of long hairs may reduce the transpiration of young leaves emerging from a shoot. The terete leaves, which are commonly found in xerophytes in deserts, can reduce the surface area to volume ratio. The plant also has a visible, beautiful network of veins in the thick leaves supporting the survival of the cells.

P. pilosa, among with species such as Sesuvium portulacastrum, Scaevola hainanensis, Tetragonia tetragonioides,  Suaeda australis, and other plants living in the seashore all have thick leaves, waxy cuticle, and relatively small flowers. As the discussion in (HKWildlife.net) suggests, this may be an example of convergent evolution in which various species adopt similar physiological features under similar survival pressures.

The photos below are taken on a hill in the New Territories. Interestingly, the population lives far from the seashore and besides a cement road. Given there are man made objects and construction going on near the site, my hypothesis is that the seeds of plant may be brought up in the delivery of construction materials.

Whole plant

Shoot, showing leave veins and white hairs

Pinkish flower, an ant seems to help pollinating it

Another flower
The structure at the right of the flower is a fruit with seeds gone

Geissapis cristata（睫苞豆 ● Geissapis）

  Geissapis cristata is an annual herb that grows in certain wetlands in Hong Kong. It seems quite uncommon locally with restricted distribution. The species is characterized by its large bracts with cilia. The bracts probably brought the plant its Chinese name, which means bracts with eyelashes. Personally, I think the bracts are used by the plant to protect the flower buds and other fragile structures from insects and other pests, but I wonder whether the structure would hinder seed dispersal too since the bracts also seems to be covering up the pods. According to Flora of Hong Kong, the pods have 1-2 segments with each segment 4mm in length. With pods this size, it is possible that the plant depends on anemochory (wind dispersal). Maybe the bracts could prevent the seeds from being blown away when the wind is not strong enough to bring the seeds to a place far away, but further studies are needed to test this hypothesis.

  I found a population of G. cristata in a piece of wetland near the seashore in Sai Kung. The location is under heavy pressure  for development and this population may very likely be completely wiped out if the development plan is implemented. It occurs to me that wetlands, with its flat nature, is extremely vulnerable to development, and sadly the government hasn't done much to protect them. It is really a pity to see that more and more wetlands with high ecological value are replaced by residential flats and houses. I really hope to see more laws and regulations targeting the protection of wetlands such as this one in the future, or else, rare wetland species such as G. cristata will very likely become locally extinct in coming years. Here are some photos of G. cristata taken in November.

Population

Leaves

Yellowish flowers

Bracts

Salomonia cantoniensis（齒果草 ● Salomonia）

Salomonia cantoniensis is a annual herb species that is widespread and common in Hong Kong. Populations of the plant usually occupy relatively dryer habitats in shrublands. The species is most common in sunny habitats. I have observed populations growing at roadsides and open habitats near country trails. This species is distinguished from the other similar species in the genus, S. ciliata（橢圓葉齒果草）, by its winged stems. S. cantoniensis bears purplish red flowers in the summer and capsules with a denticulate surface. The structure of the capsule makes me wonder what evolutionary advantage does a denticulate  surface have. My guess is that although the plant may depend on wind or gravity to disperse its seeds, the denticulate surface can facilitate dispersion by animal fur or feathers so that the seeds can be transported to a further location once in a while.

Among a hike in NT east, I discovered  a population which bears white flowers instead of the usual purplish red. This phenomenon is not described in Flora of Hong Kong and some other sources. The unusual colour is probably due to genetic mutation or a recessive gene expression. The photos below are taken in NT east in summer.

Population with white flowers

White flowers with no purple pigment

Leaves and stem of the white-flowering population. Stems are winged

A normal spike with purplish flowers

Purple flowers, the structure below are the capsules 

Winged stem of the purple-flowering population

Rhododendron championiae（毛葉杜鵑 ● Champion's rhododendron）

Rhododendron championiae is a shrub or small tree that has restricted distribution in Hong Kong. According to Flora of Hong Kong, the species can only be found in limited localities including Tai O, Ma On Shan, and Victoria Peak. Personally, I've seen the population growing in Tai O and the one on Ma On Shan. The species seems to be growing in shrublands on steep slopes. The species is characterized by its glandular hairs growing on leaves and buds, an adaptation probably used to save water and prevent insects from eating the tissues of the plant. In spring, white flowers with yellowish dots and occasionally having a touch of pink color emerge. The fruit of the plant is a capsule that holds the seeds before they are distributed by anemochory like other Rhododendron spp.. The photos below show withering flowers of R. championiae in Tai O (I was a little too late).

Flowers

New leaves

Old leaves (crowed towards the apex, in a whole like arrangement)

Flowers

Flowers

Flowers

The whole population on the slope

Utricularia caerulea （短梗挖耳草 ● Blue bladderwort）

Utricularia caerulea is a small carnivorous plant that grows in wet environments. The species is particularly common on wet rocks near streams, commonly found with other Utricularia spp.. The ecological niche of the species is somewhat similar to that of U. bifida. Both plants are usually not submerged and growing in relatively drier habitats near streams. U. caerulea bears flowers in late summer, autumn, and winter. The species has two different flower colours, white and purple. Both variations are quite common in Hong Kong. I found populations of white flowers in a few sites in Sai Kung and on Lamma Island. While I observed populations with purple flowers in Tai Lam, Hong Kong Island and in another site on Lamma Island. Surprisingly, the two varieties doesn't mix together. The two sites on Lamma Island are only a few kilometers apart but plants in a site is either purple or white, not both. It may suggest that different populations rarely cross pollinate, and the seeds do not travel far enough to another stream. Below are some photos I took in various sites.

Purple flowers

Fruits

Purple flowers

Purple flowers

Population with purple flowers only

White flower

Population with only white flowers

The damp soil in its habitat

Utricularia bifida（挖耳草/割雞芒 ● Small yellow bladderwort）

Utricularia bifida is a small carnivorous herb growing in wet places and marshes, especially in wet rocks near streams. It is the most common species in the genus, widespread in different areas. Usually, the species shares its habitat with other Utricularia spp. such as  U. uliginosa (濕地挖耳草）, U. caerulea（短梗挖耳草）,and U. striatula（圓葉挖耳草）. However, the species seems to be able to tolerate slightly drier habitats when compared with other Utricularia spp.. I once seen a flowering, healthy population growing on rocks that almost dried up and under direct sunlight, with no other Utricularia spp. growing nearby. Like other species in the genus, the plant produces traps on leaves, roots, and other submerged structure. I heard that the traps use water pressure difference to suck small aquatic organisms in, but the traps are too small for me to observe. U. bifida is characterized by its yellowish flowers. Here are some pictures taken on an outlying island, populations are also seen in streams all over Hong Kong.

Yellowish flower

Leaves (the small, long ones)

Balanophora harlandii（紅苳蛇菰 ● Harland's balanophora）

Balanophor harlandii is an interesting parasitic plant that emerges from the ground in autumn and winter. The plant can be classified as an obligate root holoparasite. The species is relatively common when compared with other root parasites and myco-heterotrophs found in Hong Kong. Maybe that is due to it's relatively large plant size which makes the species easily spotted on the forest ground.  Personally, I've seen the species in a few locations in Hong Kong Island and Kowloon. The plant is red to yellow in color resembling the shape of a mushroom in shape. As a result, many people (including me when I first saw the plant) misidentified the species as a fungi. The species seems to have completely lost its ability to photosynthesize, with leaves reduced to scale like structures. It is usually found in forests and seems to be getting its nutrition from roots of trees. The following pictures are taken in Hong Kong Island in autumn.

Plant growing out showing underground structure
(Note: I did not dig the plant up, it was like that when I saw it)

Yellowish female 

Yellowish male plant

Yellowish male flower

Older yellowish male flowers

Red female plant

Red male plant

Cropped image of female flowers

Ranunculus sceleratus（石龍芮 ● Celery-leaved crowfoot）

   Among many wetland plants, Ranunculus sceleratus is a rather uncommon one. It is a beautiful annual herb that grows in spring. The species is suited to grow in relatively colder days.

   In suitable habitats such as wet farmlands in Yuen Long, I've seen the plant growing to almost half a meter tall. I found a population of the species very close to my home and used a great deal of time to observe it. Unfortunately, that population grows in relatively dry urban environment and is often removed by gardeners, so the plants growing there are relatively short, most of the plants found there mature and start to flower when they are just a few cm tall.

   The plant has two kinds of leafs. The leaves in the lower portion of the plant is 3-partile and relatively broad. For cauline leaves, the higher the position of the leaf, the less divided it is. This adaptation is used when the plant grows in shallow water. The basal leaves floats while the cauline ones does not touch the water. Yellowish flowers could be found in the upper portion of the plant. The receptacles in the flower gets longer and longer as the flowers develop. At last, petals fall and the receptacles develop into an aggregate fruit. I'm quite curious of the dispersion method the fruits use. Since the plant could be dispersed to places far from water, it is unlikely that the plant uses water or aquatic animals to disperse its seeds. The shape of the fruit suggests that it does not rely on wind dispersal (anemochory). I suspect that the plant relies on birds to disperse its seeds but the color doesn't seem to be attractive or attention grabbing at all so it is kind of strange.

  The following pictures are taken in the population found in the urban area in spring, probably originally entered the system through the soil.

Plant in urban environment

Basal leaf

Leaf in the middle

Cauline leaf, not lobed,

Yellowish flower

Lateral view, flower

Fruit, greenish

Goodyera procera（高斑葉蘭 ● Tall rattlesnake-plantain）

There are more than one hundred species of orchids in Hong Kong. Most of these species are very rare and some even went locally extinct. Goodyera procera is one of the exceptions, it is locally common and could be found in many streams or wet places. Maybe since the species doesn't have large flowers nor ornamental value, it escaped from illegal orchid collection and remained widely distributed. Flora of Hong Kong described the ecology of the species as growing in 'earth pockets on rocks in stream bed'. This is indeed a very accurate description of where the species could be found. G. procera does not have a psuedobulb nor does it have thickened roots. It has an erect stem and does not possess a creeping rhizome. Maybe since the species is found near streams, water is ample and the plant does not have to store up water in root tissues. Small white flowers clustered on a terminal raceme could be found in spring (Flora of Hong Kong: Mar. to Apr.) The following pictures are taken in April in Ma On Shan Country Park.

Population

Growing in earth pockets of streams

Leaves

Abaxial surface of leafe

Terminal raceme

Flowers, showing typical orchid flower structure

Flowers

Base of plants with roots that are not thickened, stems upright