Senegalia propinqua (Leguminosae: Mimosoideae), a new species from the Yuanjiang dry-hot valley in south-central Yunnan Province, China is described and illustrated. It is compared with S. kunmingensis, S. macrocephala and S. teniana. A distribution map of the four species is provided.
Curcuma L. is an economically important genus in the family Zingiberaceae. Many species are grown as medicinal, culinary, and ornamental crops. As a result of their high morphological diversity and small chromosome sizes, chromosome numbers and species relationships of Chinese Curcumas remain debated. This study examined chromosome numbers of 15 populations representing 11 species of Curcuma from China. Results showed that only Curcuma flaviflora S. Q. Tong was diploid with 2 n = 2 x = 42 and C. kwangsiensis S. G. Lee & C. F. Liang was tetraploid with 2 n = 4 x = 84. The other species were triploid (2 n = 3 x = 63). The study indicated that the basic chromosome number of Curcuma from China could be x = 21. The diploid C. flaviflora produced viable seeds, which was the main means for propagation. The tetraploid and the triploids produced no seeds and relied on rhizomes for propagation. Chromosome sizes of all species were small, ranging from 0.5 to 2.1 μm, which prevented karyotype analysis. The fact that nine of 11 species studied were triploid indicates that triploidy may have some type of competitive advantage over the diploid and tetraploid. In addition, the triploids are popular commercially because of abundant rhizome production and this may contribute to their wide distributions.
Background: Bamboos, widely distributed in temperate and tropical Asia, Africa and America, refer to a group of special plants in Poaceae, Bambusoideae. China is rich in bamboo species. However, due to a long flowering cycle, the flowering habit and the flowering structure of many bamboo species are still not well understood. Here, we report a new bamboo species from Guangdong, China and an analysis of its interesting branch development in relation to flowering. Results: This species is similar to G. stellatus, the type species, but differs in the characteristics of its lemma and palea, mid-culm branch complement, and culm-sheath ligules. The initial branches at a culm node do not apically develop flowering structures during a flowering episode; instead, these form on what appears to be specialized flowering branches. Conclusions: The results of morphological comparison support the recognition of Gelidocalamus fengkaiensis as a new species. And during a flowering episode, two branch types (‘foliage branch’ and ‘flowering branch’) can be distinguished in this species.