Thai Forest Bulletin (Botany)

Two new species of Pittosporum (Pittosporaceae) for the Flora of Thailand

2020-07-09T20:59:11+07:00

Two new species of Pittosporum (Pittosporaceae) are reported for Thailand. Pittosporum lacrymasepalum from Trat Province and P. maxwellii from Doi Inthanon, Chiang Mai Province are described and illustrated.

Psammosilene tunicoides (Caryophyllaceae) a new generic and species record for Thailand

2020-07-13T16:15:45+07:00

Psammosilene tunicoides, a new generic and species record for Thailand, is reported. The new record was discovered on a degraded calcareous substrate mountain in the western part of Thailand near the Thai-Myanmar border. The species was previously reported to be endemic to SW China. This occurrence in Thailand greatly extends the distribution of the species. A lectotype is designated here.

New records of the genus Psychotria (Rubiaceae) from Thailand

2020-07-15T12:01:33+07:00

Four species of Psychotria are newly recorded from Thailand: P. bonii, P. griffithii, P. langbianensis and P. pachyphylla. Descriptions and list of synonyms are provided and a lectotype for P. bonii is designated.

Begonia colliculata (Begoniaceae), a new species from Nam Kading National Protected Area, Bolikhamxai province, Laos

2020-07-24T08:08:45+07:00

Begonia colliculata is described and illustrated with photographs from Nam Kading National Protected Area, in the Bolikhamxai Province of Laos.

Heterostemma brownii (Apocynaceae), a new record for Laos and Thailand

2020-07-30T13:20:13+07:00

Heterostemma brownii is reported as a new record for the floras of Laos and Thailand. A lectotype is also designated for the name H. brownii. A description based on Thai and Laos collections, photographs and notes are provided.

The Cenozoic leaf morphotypes and palaeoclimate interpretation from the Doi Ton Formation, Mae Sot District, Tak Province, western Thailand

2020-08-04T09:41:40+07:00

The Cenozoic palaeovegetation and palaeoclimate of Doi Ton, western Thailand, megaflora are reconstructed based on physiognomic climate analysis, including Leaf Margin Analysis (LMA), Leaf Area Analysis (LAA), Leaf Size Index (LSI), Climate Leaf Analysis Multivariate Program (CLAMP), and systematic descriptions of each leaf morphotype. The leaf fossils were divided into 23 dicotyledonous leaf morphotypes and two unknown leaf morphotypes. The mean annual temperature results from LMA indicate 32.3 ± 1.17 °C and CLAMP shows 21.2°C. CLAMP also provides temperature data of a warm month mean temperature (WMMT) of 27.4 °C and a CMMT of 14.2 °C, which is similar to the present climate. The mean annual precipitation is estimated by LAA to be ~ 125 cm. CLAMP suggests precipitation in the 11 months of growing period was 154.9 cm with the three wettest months having precipitation of 73 cm, widely contrasting with 15.5 cm for the three driest months. The precipitation shows the signal of the monsoon effect. The temperature, precipitation, and LSI mirrored the vegetation of the contemporary Doi Ton area which is a semi-evergreen forest in the tropical zone. The palaeoclimatic parameters of Doi Ton are in good agreement with those of south China and northwest
India from the Eocene period and the present-day Mae Sot area. Moreover, the Doi Ton flora also closely matches the humid subtropical modern vegetation of south China. Palaeoclimate and vegetation analysis support an Eocene age estimate for the Doi Ton Formation however further independent age estimates are required to test this working hypothesis.