Displaying 1201 - 1225 out of 1575 Object(s)
| Term | Definition | |
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| Raquis | Eje de una hoja compuesta (excluido el peciolo), o de una inflorescencia (excluido el pedúnculo); por ejemplo, en las Leguminosas, el raquis es la parte del eje de las hojas que sostiene a las hojuelas |
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| Ray flower | A zygomorphic flower with a straplike corolla found in Asteraceae. Compare with disk flower. |
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| Recepticle | The thickened part of the pedicel from which the flower organs or the fruits arise. In some accessory fruits, for example the pome and strawberry, the receptacle gives rise to the edible part of the fruit. |
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| Receptive stigma | The time when pollen grains placed on the stigma by a pollinator are able to germinate and, thus, the nuclei they contain can potentially fertilize the egg which then has the chance to grow into an embryo, then become a seedling, and finally a reproductive plant itself. |
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| Recurved | Curved backward. |
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| Reed stem | In some Orchids (e.g. Epidendrum), this term refers to having stems that are long and relatively slender, commonly with leaves scattered along the stem. |
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| Reflexed | Abruptly bent backward or downward. |
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| Regular flower | A flower, capable of being divided, by more than one line passing through the middle of the flower, into two equal parts that are mirror images of one another; e.g., in Gustavia (Lecythidaceae), species of Myrtaceae, and species of Rubiaceae. Same as actinomorphic, polysymmetric, and radially symmetrical flowers and opposite of zygomorphic, monosymmetric, bilateral, and irregular flowers. This term can refer to other plant parts as well. |
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| Reniform | Kidney-shaped. |
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| Repent | Creeping flat along the ground, usually referring to stems growing along the ground that produce roots at their nodes. Same as prostrate. |
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| Replum | A thin membrane that runs from one side of the fruit to the other side of the fruit in many Brassicaceae that persists after the fruits have dehisced and the seeds have been dispersed, i.e., it is the partition between the two compartments or locules of the fruits. |
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| Reproductive biology | In this glossary, all terms that refer to asexual and sexual reproduction in the broadest sense. |
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| Respiration | In plants, the process of oxidizing sugars to obtain energy for growth and reproduction. This yields carbon dioxide and water as byproducts. |
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| Restinga | Portuguese term referring to a diverse array of vegetation found on sandy soil in a narrow band along the Brazilian coast between the high-tide mark and taller forests farther inland. |
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| Resupinate | Turned 180° in development; e.g., flowers of the Orchidaceae in which the lip originates in the uppermost position but twists 180° so it facing downward at anthesis. Most orchids have resupinate flowers. |
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| Reticulate | Netted, like the veins of many leaves. |
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| Reticulate tertiary venation | Tertiary venation anastomosing with other tertiary veins or with the secondary veins (Hickey, 1973) |
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| Reticulate venation | Referring to the venation of a leaf which forms a network. |
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| Retrorse | Directed downward or backward. Opposite of antrorse. |
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| Retuse | Notched slightly at the apex. |
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| Revolute | With the margin inrolled toward the abaxial surface. Compare with involute. |
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| Rhizome | A prostrate stem below the ground that sends off rootlets and vertical stems or leaves; in the Poaceae, lateral underground stems that collectively constitute a “sod” from which leafy stems emerge. |
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| Rimose | Fissured or cracked, as the bark of some trees. |
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| Ring nectary (= nectary ring-like) | A raised, circular ridge found between the attachment of the androecium and the base of the style that produces nectar. |
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| Riparian | Referring to plants and animals that growi or live along streams or rivers. |
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