To understand the evolution of seed character in Brassicales, we investigated the mature seed morphology and anatomy of four species in all three, poorly understood genera of Salvadoraceae (Azima, Dobera, and Salvadora). The seeds of Salvadoraceae are straight (i.e., not reniform), exarillate, and exalbuminous with a straight embryo. The seed coat is composed of only a testa and lacks a tegmen (including an exotegmen). The thick, multiplicative (except in A. sarmentosa) testa has no vascular bundles. The combination of seed and seed coat characteristics supports Salvadoraceae as distinct from the other Brassicales. Evolutionary trends in seed and seed coat (integumentary) characters in Brassicales, particularly the relationships of Salvadoraceae with Bataceae and Koeberliniaceae, are briefly discussed.
Previous floristic studies of Podostemaceae in Thailand recorded four species assigned to two genera in Loei Province, northeastern Thailand. Our explorations and taxonomic studies have resulted in six genera and 12 species from the Province, including four new species (Terniopsis heterostaminata, T. filiformis, Hydrobryum phurueanum, and H. varium), two new records to Thailand (H. vientianense and Polypleurum pluricostatum), two new records to Loei (Dalzellia kailarsenii and Thawatchaia trilobata), and new localities in Loei of the remaining four species. All species are strictly or moderately narrowly distributed, but H. japonicum is widely distributed. The species of Terniopsis differ from each other and from their congeners by the number of stamens, the length of the stamens relative to ovary, and the form of the stigmas. The new species of Hydrobryum are distinct in the caudate or acuminate long bract and in the long pedicel. Hydrobryum is the largest genus in Loei with six species. Four or five species occur densely in each of three rivers constituting a single river system in the Province. Loei is among the most species-rich areas in Thailand due to the mostly mountainous topography.
We examined morphological differentiation and allozyme diversity in nine populations of Vincetoxicum katoi and its close relative V. yamanakae. Although, V. yamanakae has been distinguished from V. katoi in having a larger corolla and gynostegium, the principal component analysis based on 12 floral and three leaf characters did not support the distinction of the two taxa. The six allozyme loci examined revealed that population of V. katoi and V. yamanakae maintained high genetic diversity (P=72.1, A=2.40, h=0.313). The nine populations were clustered into three regions (Kanto-Tokai; middle Kiniki; and Kii-Shikoku) based on genetic differences, contradicting the current taxonomic treatment. Considering the evidence, it is appropriate to treat V. yamanakae as a synonym of V. katoi. The high genetic differentiation among regions suggested that disjunct distribution of the V. katoi-V. yamanakae complex might reflect the persistence of refugia since the last glacial period. In particular, the middle Kinki (Hyogo) population is located outside of known evergreen forest refugia, suggesting that it might have survived during the glacial period within cooler vegetative zones, such as in temperate forests, whereas the populations on the Pacific-side retreated to warm-temperature coastal refugia.
Myristicaceae, a family with pantropical distribution and sister to the rest of the Magnoliales, are poorly understood with respect to chromosome numbers. Here we report somatic chromosome numbers of 14 species in five of the six Asian genera. Chromosome numbers were consistent within individual genera but markedly differ among the genera. Based on our observations, we concluded that the generic base number is x=20 in Endocomia, x=22 in Gymnacranthera and Knema, x=25 in Myristica, and x=26 in Horsfieldia. Although reliable data on chromosome numbers are currently limited to Asian genera, a great divergence in base numbers is a marked contrast to the low molecular divergence within the family, casting a doubt to dating Myristicaceae to be young.
Impatiens talakmauensis Utami (Balsaminaceae), a new species from Pasaman (Mt. Talakmau) western Sumatra, Indonesia, is newly described. It is characterized by yellow flowers, united lateral petals, reddish purple flushed veins of the lateral petals and the lower sepal. The lower sepal deeply navicular and abruptly constricted into a curved, short, pale yellow spur. The species was found in limestone areas of Mt. Talakmau, western Sumatra.