from The American Heritage® Dictionary of the English Language, 5th Edition.
- adjective Having three similar segments or parts.
- adjective Botany Having flower parts, such as petals, sepals, and stamens, in sets of three.
from The Century Dictionary.
- In botany, of three members; having the parts or members three in each cycle. Frequently written 3-merous.
- In entomology: Divided into three joints; having three segments, as the tarsus of a beetle, thus:
- Having the tarsi normally three-jointed, as a beetle; of or pertaining to the Trimera. Also
from the GNU version of the Collaborative International Dictionary of English.
- adjective (Bot.) Having the parts in threes.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- adjective botany Organized in
threes; having parts in numbersthat are multiplesof three.
from Wiktionary, Creative Commons Attribution/Share-Alike License
Thus trimerous fuchsias and tetramerous jasmines may frequently be met with, and Turpin describes a tetramerous flower of _Cobæa scandens_.
So in fuchsias, a very common deviation consists in a trimerous and rarely a dimerous symmetry of the flower.
It differs from P. virginiana in its longer leaves, brittle branches, and much greater height, from P. glabra in its rough upper trunk, and from both by the frequent presence of trimerous leaf-fascicles.
Another group, with trimerous fascicles, contains P. Sabiniana and P. taeda.
From the former it differs in leaf-section and bud (the bud of P. sinensis is never white), from the latter in the lustre and the color variation of its cone, and from both in the frequent obliquity of its cone and in the frequent presence of trimerous leaf-fascicles.
Would you not consider as a morphological difference the trimerous, tetramerous, etc., divisions of flowers, the ovules being erect or suspended, their attachment being parietal or placental, and even the shape of the seed when of no service to the plant.