Showing posts with label Fabaceae(蝶形花科). Show all posts
Showing posts with label Fabaceae(蝶形花科). Show all posts

Wednesday, January 7, 2015

Sophora tomentosa(絨毛槐 ● hairy sophora)

Sophora tomentosa is a tall shrub species that can be found on beaches and places near the coast. The speices is rare in Hong Kong and can only be found in several outlying islands or beaches in the Sai Kung district. Although rare locally, S. tomentosa is distributed worldwide. The shrub is characterized by its dark green compound leaves with recurved leaf margins. The leaf shape and the hairs on the leaf may be used by the plant to tolerate the rather harsh conditions near the seashore. The plant produces yellowish green pods in winter, the shape of the pods gives the species and its varieties another name -- the necklace pod. I am quite curious about how the pods disperse. They seem too large for a bird to consume, maybe the pods could float on the sea across outlying islands? I will try to examine the pods next time I see them.

Flora of Hong Kong states the flowering period as mid-summer and the fruiting season as winter, but flowers and fruits are both observed during my visit to the plant in mid-December. Here are some photos taken from a beach in Sai Kung.

Plant on sandy beach

Dark green leaves

Hairy abaxial leaf surface

Yellowish flowers 

Yellowish flowers

Necklace-like pods

Necklace-like pods

Tuesday, July 22, 2014

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