GLOSSARY 



Abaxial. Situated on the side away from the axis or stem. 



Accessory fruit. A fruit consisting of a ripened ovary and other ripened parts, as the 



calyx or receptacle. 

 Acropetal. An order of development in which the youngest structures are at the apex 



and the oldest at the base. 

 Actinomorphic. Having flowers with radial symmetry, the parts extending outward 



from a common center like the spokes of a wheel. 

 Adaxial. Situated on the side toward the axis or stem. 



Adventitious. Arising sporadically without order or out of the usual place, as a bud. 

 Aeciospore. In various rust fungi, one of the spores produced in an aecium. 

 Aecium. A cup-like structure in the life cycle of a typical rust, producing spores in 



chains. 

 Aerobic. Living or active only in the presence of free oxygen. 

 Aggregate fruit. A fruit consisting of a group of consolidated ripened ovaries derived 



from a single flower. 

 Akinete. In certain algae, a nonmotile, thick-walled resting spore derived from an 



entire vegetative protoplast whose wall becomes the wall of the spore. 

 Alternation of generations. The presence in the same life cycle of two distinct plant 



bodies or individuals that succeed each other, a haploid body (gametophyte) pro- 

 ducing gametes and a diploid body (sporophyte) producing spore^^. 

 Ament. A catkin, or scaly spike. 



Amphicribral. A vascular bundle with phloem surrounding the xylem. 

 Amphigastrium. One of the reduced ventral leaves in a leafy liverwort. 

 Amphiphloic. A siphonostele with phloem both external and internal to the xylem. 

 Amphithecium. In bryophytes, the outer layer of cells developed in the young 



sporophyte. 

 Amphivasal. A vascular bundle with xylem surrounding the phloem. 

 Anaerobic. Living or active in the absence of free oxygen. 



Anatropous. Having the ovule inverted and straight, with the micropyle bent down- 

 ward to the funiculus, to which the body of the ovule is united. 

 Androspore. In such algae as Oedogonium, a zoospore that produces a dwarf male 



filament. 

 Anisocarpic. Flowers in which the number of carpels is not equal to that of each of 



the other cycles. 

 Annulus. A ring or ring-like part, as in a mushroom, a moss capsule, or a fern 



sporangium. 

 Anther. The pollen-bearing part of a stamen. 

 Antheridium. The sperm-producing organ in thallophytes, bryophytes, and pterido- 



phytes. 

 Anticlinal. Inclined in an opposite direction; a cell wall perpendicular to the outside 



surface. 

 Antipodal. Pertaining to the opposite end, as the cells or nuclei in an embryo sac at 



the end opposite the egg. 

 Apetalous. Without petals but with sepals. 



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