is a genus with some 120 species worldwide, especially in warm areas. The genus includes some crops, some ornamentals but mostly species that are considered weedy. The name of one of the weedy species Pennisetum setaceum (Forssk.) Chiov. is also found on labels of ornamental grasses as P...
There are three main types of bonding in chemistry. What is the name of the weakest forces? Which of the following compounds is expected to have the strongest ionic bonds? A. MgO B. KBr C. NaI...
If the difference in electronegativity between two atoms in a molecule is very large, the forces holding the atoms together are likely to be: a. dipole-dipole b. ionic c. non-polar covalent d. hydrogen bonds Which of the follo...
They are polyphyletic and the category is not a natural one. 指植物的某一类群是由多于一个祖先类群分化来。 Rudall et al., 2000 morphology + rbcL + trnL-F 2. Primitive evolutionary characters 原始和进化性状 1)自然界的突变和变异(mutation and differentiation) 2)自然选择(natural selection)起到删...
The genus includes some crops, some ornamentals but mostly species that are considered weedy. The name of one of the weedy species Pennisetum setaceum (Forssk.) Chiov. is also found on labels of ornamental grasses as P. setaceum "Rubrum." It has been debated to belong to a specie...