| Acanthus | Acanthaceae | Acanthaceae is a family (the acanthus family) of dicotyledonous flowering plants containing almost 250 genera and about 2500 species. Most are tropical herbs, shrubs, or twining vines; s |
| Adder's-Tongue family | Ophioglossaceae | The Ophioglossidae are one of the groups traditionally known as eusporangiate ferns. Members of the family differ from other ferns in a number of ways. Many have only a single fleshy leaf at a time. Their gametophytes are subterranean and rely on fungi for energy. |
| Agave family | Agavaceae | Course herbs or subshrubs, the stems absent or short and woody; leaves all basal, evergreen. |
| Amaranth family | Amaranthaceae | Annual or perennial herbs; leaves alternate or opposite, simple, usually entire; flowers bisexual or unisexual, regular, in various clusters, often congested and with colorful bracts; fruit a utricle. |
| Amaryllis family | Amaryllidaceae | Perennial herbs from bulbs; leaves basal, flat and parallel-veined; toxic if ingested; position of ovary varies by subfamily, the Agapanthoideae and Allioideae have superior ovaries, while the Amaryllidoideae (e.g.--- Daffodil) have inferior ovaries. |
| Arum family | Araceae | Perennial herbs from corms or tubers; leaves basal or alternate, often somewhat net-veined, simple or compound; flowers unisexual or bisexual, regular, on a spadix subtended by a spathe; fruit a berry or utricle. |
| Asparagus family | Asparagaceae | Asparagus family, is a family of flowering plants, placed in the order Asparagales of the monocots. The family name is based on the edible garden asparagus |
| Asphodel | Asphodelaceae | Members of the Asphodelaceae are diverse, with few characters uniting the three subfamilies currently recognized. The presence of anthraquinones is one common character. The flowers (the inflorescence) are typically borne on a leafless stalk (scape) which arises from a basal rosette of leaves. The individual flowers have jointed stalks (pedicels). A disk of woody tissue (a hypostase) is present at the base of the ovule. [1] |
| Aster family | Asteraceae | Flowers of two basic types: 1) disk florets with tubular corollas, and 2) ray florets with ligulate corollas. Heads are composed of exclusively one type or the other (discoid or ligulate), or typically with disk florets in the center and ray florets around the perimeter; fruit an achene (or cypsela). |
| Barberry family | Berberidaceae | Perennial herbs or spiny shrubs with yellow wood; leaves alternate; flowers bisexual, regular; fruit a berry or capsule. |
| Basswood family | Tiliaceae | Large deciduous trees; leaves alternate, simple, cordate-oblique, serrate, stipulate; flowers bisexual, regular, in cymose clusters on leafy bracts; fruit nutlike. |
| Beech family | Fagaceae | Deciduous trees; leaves alternate, simple, stipulate; flowers unisexual, regular, in catkins or spikes or solitary; fruit a nut subtended by an involucre (spiny bur or scaly cup). |
| Begonia family | Begoniaceae | The Begoniaceae consists of two genera: Begonia, with some 1,000 species, and Hillebrandia. A majority of species are perennial herbs, some climbing, with succulent stems and thick rhizomes or tubers; some species are shrubs. |
| Bellflower family | Campanulaceae | Annual, biennial, or perennial herbs; leaves alternate, simple; flowers bisexual, regular or irregular, in cymes or racemes; fruit a capsule, opening by valves or pores. |
| Birch family | Betulaceae | Deciduous trees and shrubs; leaves alternate, simple, stipulate; plants monoecious, with flowers bracteate in catkins, the staminate catkin pendulous and pistillate catkin spikelike or conelike; fruit a nut, nutlet, or tiny samara. |
| Birthwort family | Aristolochiaceae | Herbs or woody vines; leaves alternate, palmately veined; flowers bisexual, axillary and often solitary; fruit a capsule; family exhibits both monocot and dicot characteristics, and recent studies have placed Aristolochiaceae in a group called "paleoherbs," suggesting a close ancestral alliance with the monocots. |
| Bittersweet family | Celastraceae | Vines, shrubs, or small trees; leaves opposite or alternate, simple; flowers bisexual, regular, in axillary cymes; fruit a capsule with arillate seeds. |
| Bladdernut family | Staphyleaceae | Shrubs with striped bark; leaves opposite, trifoliate, stipulate; flowers bisexual, regular, in drooping panicles; fruit a bladdery capsule. |
| Borage family | Boraginaceae | Annual and perennial herbs; leaves alternate, simple, entire; flowers bisexual, in helicoid cymes, regular or irregular; fruit of 1-4 nutlets; several species considered toxic. |
| Box family | Buxaceae | A small family of six genera and about 123 known species[2] of flowering plants. They are shrubs and small trees, |
| Bracken family | Dennstaedtiaceae | Sporangia-bearing; bracken fronds toxic if eaten. |
| Broomrape family | Orobanchaceae | Non-green (lack chlorophyll), root-parasitic (on the roots of deciduous trees), perennial herbs; leaves alternate or densely overlapping, scalelike; flowers mostly bisexual, irregular, solitary or in spikes; fruit a capsule. |
| Buckeye family | Hippocastanaceae | Shrubs or trees; leaves opposite, palmately compound, flowers mostly bisexual, irregular, in panicles; fruit a dehiscent capsule with 1-3 seeds (buckeyes), these large and smooth, with conspicuous pale scar. |
| Buckthorn family | Rhamnaceae | Woody vines, shrubs, and small trees; leaves alternate or opposite, simple, stipulate; flowers bisexual or unisexual, regular, in panicles or axillary clusters; fruit various, the seeds with hard endocarps. |
| Bur-Reed family | Sparganiaceae | A family of monocotyledonous plants in the order Typhales distinguished by the inflorescence of globose heads, a vestigial perianth, and achenes that are sessile or nearly sessile. |
| Buttercup family | Ranunculaceae | Annual or perennial herbs, woody vines, and low shrubs; leaves various, often basal and alternate, simple to compound; flowers bisexual or unisexual, regular or irregular, in various clusters; fruit variable, most frequently a follicle or achene; family contains many highly poisonous plants. |
| Butterfly-Bush family | Buddlejaceae | Woody plants or herbs; leaves opposite, simple, linear to lanceolate, stipulate; flowers bisexual, regular, in cymes or panicles; fruit a capsule. |