COROLLA LOBES SEPARATE STIGMA STAMEN PETAL SEPAL FLOWER-STALK (PEDUNCLE) COROLLA LOBES UNITED COROLLA LOBE STAMEN ANTHER (POLLEN-SAC) FILAMENT SEPAL PISTIL STIGMA STYLE OVARY CALYX-TUBE SEED STIGMA STAMEN SEPAL CALYX-TUBE CAPSULE BELL-SHAPE CALYX-TUBE TUBULAR FUNNEL FORM COMPOSITE FLOWER HEADS INVOLUCRE STIGMA STYLE STAMEN TUBE DISK COROLLA RAY COROLLA DISK FRUIT BRACT (FLORAL LEAF) FLORAL LEAF (BRACT) LEAF BLADE MIDRIB LEAF-STALK (PETIOLE) IRREGULAR LOBES FRUIT OF COMPOSITE (ACHENE) BRISTLES (PAPPUS) SEED SIMPLE LEAVES LINEAR LANCE-SHAPE OBLONG LANCE-OBLONG OVATE COMPOUND LEAVES ONCE-DIVIDED PALMATE or DIGITATE SHARPLY TOOTHED LEAFLETS LEAF-STALK (PETIOLE) STEM PINNATE TWICE-DIVIDED LEAFLET LEAF-STALK
The diagram on the opposite page carries illustrations of most of the terms used in the following descriptions of plants. As it was intended that this manual should serve as a means of plant identification from illustrations, the descriptions have been made very brief. If the reader is interested in a more detailed description, technical books should be consulted. Some botanical terms are rather loosely used in the effort to avoid technical expressions; for example, the fruit of a daisy flower is known popularly as a seed but is an achene, a seed closely covered by the wall of the ovary.
The conspicuous parts of the flower commonly make up the corolla, each part being known as a petal; however, in some flowers the showy part is actually the calyx, as the outer whorl of parts around the stamens and pistil is always called. The divisions of the calyx are known as sepals. The stamens are made up of two parts—the anthers or small sacs which bear the pollen grains, a necessary part to fertilization, and the filaments or stalks which elevate the anthers so that the pollen grains can be scattered. The ovules which develop into seeds after fertilization are borne in the ovary, a part of the pistil. The pollen is deposited on the stigma and carried down the style to the ovule. Showy flower parts, nectar, and other devices attract insect visitors which aid in the transfer of pollen from one flower to another.
In order that botanists everywhere may make use of plant names and descriptions, these are written in Latin. The Latin name of the bluebonnet is _Lupinus texensis_, in which _texensis_ represents the name of a species and _Lupinus_ is the name of a genus, which is a group of closely related species. The plants making up the different species in a genus are usually so much alike in flower, fruit, and leaf characters that they can be recognized as belonging to the same group. Similar genera (plural of genus) are grouped together in families; the family name in Latin takes the ending -_aceae_. Thus while this book illustrates only 257 Texas plants, it is hoped that the reader will become familiar with many others which bear a close relationship.