The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . eaA-es, stillsmaller, growing upon the pedicels, are called hractlets. Bractsare usually simple in outline and smaller than the leaf, oftengradually diminishing to mere points, as in Aster, or even totally IIG STRUCTURAL BOTANY. suppressed, as in the Cruciferae. Often they are colored, some-times brilliantly, as in Painted-cup. Sometimes they are scale-
The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . eaA-es, stillsmaller, growing upon the pedicels, are called hractlets. Bractsare usually simple in outline and smaller than the leaf, oftengradually diminishing to mere points, as in Aster, or even totally IIG STRUCTURAL BOTANY. suppressed, as in the Cruciferae. Often they are colored, some-times brilliantly, as in Painted-cup. Sometimes they are scale-like, and again they are evanescent membranes. 346. The Spathe is a large bract formed in some of the Mono-cotyledons, enveloping the inflorescence, and often colored, as inArum, Calla; or membranous, as in Onion and Daffodil. 347. Bracts also constitute an Involucre when they are col-lected into a whorl or spiral group. In the Phlox, Dodecatheon,and generally, the involucre is green, but sometimes colored andpetaloid, as in Dogwood and Euphorbia. Situated at the baseof a compound umbel, it is called a general involucre; at thebase of a partial umbel it is a partial involucre or involucel,both of which are seen in the Umbelliferffi. 436. 433, lleliauthus grosse-serratus—?, involucre; r, rays, or ligulate flowers. 434, One of the disk-flowersWith its chafi-scale (bract). 435. Acorn of Moss-cup Oak (Q. macrophylla). 436, Poa pratensis—/, spike-let entire; g, glumes separated; c, a flower separated, displaying the two pales, 3 stamens and 2 styles. 348. In the Compositse, where the flowers are crowded upon acommon torus, forming what is called a compound flower^ an in-volucre composed of many imbricated scales (bracts) surroundsthem as a calyx surrounds a simple flower. The chaff also uponthe torus are bracts to which each floret is axillary (434). 349. In the Grasses, the bracts subsist under the general nameof chaff. At the base of each spikelet (436) of flowers we findtwo b
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1870
