Friday, 6 March 2020

Acid Sulfate Soil

Acid sulfate soils are naturally occurring soils, sediments or organic substrates (e.g. peat) that are formed under waterlogged conditions.

These soils contain iron sulfide minerals (predominantly as the mineral pyrite) or their oxidation products. In an undisturbed state below the water table, acid sulfate soils are benign.

However, if the soils are drained, excavated or exposed to air by a lowering of the water table, the sulfides react with oxygen to form sulfuric acid.

Release of this sulfuric acid from the soil can in turn release iron, aluminium, and other heavy metals (particularly arsenic) within the soil.

Once mobilized in this way, the acid and metals can create a variety of adverse impacts : killing vegetation, seeping into and acidifying groundwater and surface water bodies, killing fish and other aquatic organisms, and degrading concrete and steel structures to the point of failure.

Chemical reaction

When drained, pyrite- (FeS2) containing soils (also called cat-clays) may become extremely acidic (pH < 4) due to the oxidation of pyrite into sulfuric acid (H2SO4)..

2FeS2 + 9O2 + 4H2O 8H+ + 4SO42- + 2Fe(OH)3

Fe(OH)3, iron(III) hydroxide (orange), precipitates as a solid, insoluble mineral by which the alkalinity component is immobilized, while the acidity remains active in the sulfuric acid.

The process of acidification is accompanied by the formation of high amounts of aluminium (Al3+, released from clay minerals under influence of the acidity), which are harmful to vegetation.

Other products of the chemical reaction are:
1. Hydrogen sulfide (H2S), a smelly gas
2. Sulfur (S), a yellow solid
3. Iron(II) sulfide (FeS), a black/gray/blue solid
4. Hematite (Fe2O3), a red solid
5. Goethite (FeO.OH), a brown mineral
6. Schwertmannite, a brown mineral
7. Iron sulfate compounds (e.g. jarosite)

8. H-Clay (hydrogen clay, with a large fraction of adsorbed H+ ions, a stable mineral, but poor in nutrients)

Tuesday, 3 March 2020

Wild Ficus of Seremban

 Ficus subpisocarpa

Ficus subpisocarpa ( called 笔管榕 in China and 雀榕 in Taiwan ) is a species of small deciduous tree native to Japan, China, Taiwan and southeast Asia to the Moluccas.  The figs are ramiflorous, that is the fruit grow on the branches.

Two subspecies are recognized  : pubipoda and  subpisocarpa

Ants predominantly of the genus Crematogaster have been recorded living in stem cavities. Ficus subpisocarpa is pollinated by Platyscapa ishiiana (Agaonidae).

Ficus hispida

Ficus hispida ( 对叶榕 ) is a small but well distributed species of tropical fig tree. It occurs in many parts of Asia and as far south east as Australia.   An unusual feature is the figs which hang on long stems.

Two subspecies are recognized  : rubra and  badistrigosa

In Australia the fruit are eaten by cassowaries and double-eyed fig parrots. Phayre's leaf monkey feeds on the leaves as do the larvae of the moth Melanocercops ficuvorella. The fig wasp Apocrypta bakeri has F. hispida as its host, where it parasitizes the other fig wasp Ceratosolen solmsi.

 Ficus grossularioides

Two varieties are recognized  : stenoloba and  kingii .

Young shoots are eaten raw; decoctions of leaves are used to treat kidney complaints.  Latex is used against scorpion bites.

Bouea oppositifolia - kundang

Bouea angustifolia Bl.
Bouea brandisiana Kurz
Bouea burmanica Griff.
Bouea burmanica var. kurzii Lecomte
Bouea burmanica var. microphylla (Griff) Engl.
Bouea burmanica var. roxburghii Lecomte
Bouea diversifolia Miq.
Bouea gandaria Blume
Bouea microphylla Griff.
Bouea myrsinoides Bl.
Cambessedea oppositifolia (Roxb.) Wight & Arn. ex Voigt
Haplospondias brandisiana (Kurz) Kosterm.
Manga acida Noronha
Mangifera oppositifolia Roxb.
Mangifera oppositifolia var. microphylla (Griff.) Merr.
Mangifera oppositifolia var. roxburghii (Pierre) Tard.
Matania laotica Gagnep.

Fruits are edible and are sometimes made into preserve when in a half ripe state. The durable, hard timber is used for various purposes.

Southern China, Indochina, Myanmar, Thailand, Andaman Islands, Malay Peninsula, Sumatra, Java; Borneo.

Local names
Borneo: asam djanar, bandjar, kedjauw lepang, tampusu, ramania pipit, umpas.
Indonesia: Asam djanar; Bandjar; Kedjauw lepang; Kundang rumania; Ramania hutan; Ramania pipit; Rengas; Tampusu; Tolok burung; Umpas.
Malay Peninsula: gemia, kemiinia, kimdang, kiidang rumenia, merapoh rumenia, poko rummiyah, rambainyia, ramimia, romaniah, rumboi-nigor, rumenia, rumia.
Sumatra: kaju-rusun, kunangan, raman burung, raman padi, raman utan, rieden daun, gandaria, raman, iiris, iirisan.

Friday, 28 February 2020

A Resolution of the Eugenia-Syzygium Controversy

Floral anatomy now provides additional, strong evidence confirming the distinctness of the mainly New World Eugenia s. s. and the strictly Old World Syzygium s. I. Most significantly, species of Eugenia s. s. have a transeptal vascular supply to the ovules whereas those of Syzygium s. I. have an axile one. Other features of floral histology and vasculature also support such a division. In addition, a review of the taxonomic literature revealed three hitherto neglected organographic criteria-nature of bracteoles, presence or absence of pubescence, and presence or absence of pseudopedicels-that sharply distinguish between Eugenia s. s. and Syzygium s. I. An ensemble of these and other organographic criteria further demonstrates the basic disparity of these taxa. The organography and histology of flowers of Eugenia s. I. are described in detail, with .26 characters contrasting the Old and New World species included in a table.

RUDOLF SCHMID, 1972, Amer. 1. Bot. 59(4): 423-436. 1972., Amer. 1. Bot. 59(4): 423-436. 1972.

Thursday, 27 February 2020

Asystasia gangetica

The genus Asystasia belongs to the family Acanthaceae and comprises approximately 70 species found in the tropics.
The generis name Asystasia is derived from the Greek words “a” and “systasia” meaning “not consistent”,  in reference to the flowers which are radially symmetrical.

The specific name gangetica refers to the Ganges river in India.


Three taxa of Asystasia, the naming of which has been confused, occur in Malaya. None is native.
1.  A. nemorum Nees (syn. A. intrusa Blume, non (Forssk.) Nees) from Java has only been collected from Penang and Singapore.
2. A. gangetica (L.) T. Anderson is widespread and is represented by two subspecies:
a. a large-flowered taxon, subsp. gangetica (syn. A. coromandeliana Nees) which is a long-established introduction from India,  and
b. a small-flowered taxon, subsp. micrantha (Nees) Ensermu ( A. intrusa syn. A (Forssk.) Nees) which is a recent introduction, probably from Africa.

R. Kiew & K. Vollesen, Asystasia ( Acanthaceae in Malaysia, Kew Bulletin, Vol 52. Bi.4 (1997), pp965-971

Saturday, 22 February 2020

Mimosa quadrivalvis

Mimosa quadrivalvis L(L.) Merr.
Fourvalve mimosa

native :
tropical America and the Caribbean

Leptoglottis quadrivalvis (L.) Britton & Rose
Morongia aculeata A.Heller
Schrankia aculeata Willd.
Schrankia mexicana Raf.
Schrankia quadrivalvis (L.) Merr.

varieties :
Mimosa quadrivalvis var. angustata 
Mimosa quadrivalvis var. floridana  
Mimosa quadrivalvis var. hystricina
Mimosa quadrivalvis var. nelsonii 
Mimosa quadrivalvis var. leptocarpa 
Mimosa quadrivalvis var. quadrivalvis          
Mimosa quadrivalvis var. urbaniana 

Sunday, 16 February 2020

A Walk Through the Tamu Sarikei 2020 CNY ( Fauna )

Decapoda Protunidae

Decapoda | Palaemonidae

Gastropoda | Potamididae

Gastropoda | Semisulcospiridae

Gastropoda | Neritidae

Bivalvia | Veneridae

Actinopteryii | Monacanthidae

Actinopteryii | Lutjanidae 

Actinopteryii | Carangidae 

Insecta | Curculionidae