ÆRUGINOUS, having the color of verdigris. ÆSTIVATION, the arrangements of the parts of the flower in the flower-bud. AGGLOMERATED, collected in a heap or head. AGGREGATE, gathered together. ALA, a wing, applied to the lateral petals of papilionaceous flowers, and to membranous appendages of the fruit, as in the elm, or of the seed, as in pines. ALBUMEN, the nutritious matter stored up with the embryo within the seed, called also Perisperm and Endosperm. ALBURNUM, the outer young wood of a dicotyledonous stem. ALEXIPHARMIC, that which counteracts poisons. ALGOLOGY, the study of sea-weeds. ALTERNATE, arranged at different heights on the same axis, and toward different sides. ALVEOLÆ, regular cavities on a surface, as in the receptacle of the sunflower, and in that of _Nelumbium_. ALVEOLATE, like a honeycomb. AMENTUM, a catkin, or deciduous unisexual spike; plants having catkins are _Amentiferous_. AMNIOS, the fluid or semi-fluid matter in the embryo-sac. AMORPHOUS, without definite form. AMPHISARCA, an indehiscent, multilocular fruit, with a hard exterior, and pulpy round the seeds, as seen in the Baobab. AMPHITROPAL, an ovule, curved on itself, with the hilum in the middle. AMPLEXICAUL, embracing the stem over a large part of its circumference. AMPULLA, a hollow leaf, as in _Utricularia_. AMYLACEOUS, starch-like. ANASTOMOSING, inosculation of vessels. ANASTOMOSIS, union of vessels; union of the final ramifications of the veins of a leaf. ANATROPAL, an inverted ovule, the hilum and micropyle being near each other, and the chalaza at the opposite end. ANCEPS, two-edged. ANDRŒCIUM, the male organs of the flower. ANDROGYNOUS, male and female flowers on the same peduncle, as in some species of _Carex_. ANDROPHORE, a stalk supporting the stamens, often formed by a union of the filaments. ANFRACTUOSE, wavy or sinuous, as the anthers of _Cucurbitaceæ_. ANGIOSPERMOUS, having seeds contained in a seed-vessel. ANISOSTEMONOUS, stamens not equal in number to the floral envelopes, nor a multiple of them. ANNOTINUS, a year old. ANNULUS, applied to the elastic rim surrounding the sporangia of some ferns, also to a cellular rim on the stalk of the mushroom, being the remains of the veil. ANTERIOR, same as inferior when applied to the parts of the flower in their relation to the axis. ANTHELMINTIC, a vermifuge. ANTHER, the part of the stamen containing pollen. ANTHERIDIUM, the male organ in cryptogamic plants, frequently containing moving filaments. ANTHERIFEROUS, bearing anthers. ANTHEROZOIDS, moving filaments in an antheridium. ANTHESIS, the opening of the flower. ANTHOCARPOUS, applied to fruits, formed by the ovaries of several flowers. ANTHODIUM, the capitulum or head of flowers or the Composite plants.