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The traditional dicots are thus a paraphyletic group. [4] The eudicots are the largest monophyletic group within the dicotyledons. They are distinguished from all other flowering plants by the structure of their pollen. Other dicotyledons and the monocotyledons have monosulcate pollen (or derived
In contrast, most of the other seed plants (that is the gymnosperms, the monocots and the paleodicots) produce monosulcate pollen, with a single pore set in a differently oriented groove called the sulcus. The name "tricolpates" is preferred by some botanists to avoid confusion with the dicots, a nonmonophyletic group. [7]
The Reveal system used the name Magnoliopsida for a group of the primitive dicotyledons, corresponding to about half of the plants in the magnoliids: class 1. Magnoliopsida superorder 1. Magnolianae; superorder 2. Lauranae
Dahlgren ranked the dicotyledons and monocotyledons as subclasses of the class of flowering plants (angiosperms) and further divided them into superorders. Originally (1975) he used the suffix -anae , as did Cronquist , to designate these, but in 1980 changed this to -florae in accordance with Thorne .
However, internal seed structure is vastly different between these groups. The cotyledon is the embryonic leaf within a seed; monocots have one whereas dicots have two. The evolution of having one or two cotyledons may have arisen 200-150 Mya when monocots and dicots are thought to have diverged.
The paired cotyledon s of a castor bean seedling (Ricinus communis) are typical of a dicotyledon. Discolorous leaves of Brachylaena discolor differ in color between their upper and lower surfaces. Disk florets opening in a capitulum of a cultivated Helianthus .
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
The Crassulaceae (/ ˈ k r æ s j uː l eɪ s iː ˌ iː,-s i ˌ aɪ /, from Latin crassus, thick), also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a form of photosynthesis, known as Crassulacean acid metabolism (CAM). Flowers generally have five ...