Page:The New International Encyclopædia 1st ed. v. 10.djvu/704

* INTLORESCENCi:. 618 INFLUENZA. In the bolryose type no Hower stand§ upun the end of the axis, whieh therefore may continue its growth iiiilehnilely (hemr an ■iiidiU-riiiiiiaU' iu- llore5<.-ence ). As a lousetiueiiee, the llmvcrbuds ctiiliiiue to apijear at or near the growing; li|) ol the axis, and since the older llowers are below, this method is called acropclal or unccnding. 'iliere are numerous forms of the botryosc tyiK-, conspicuous among which arc the following: Uuvime, in which each flower, upon its own stalk, stands upon an elongated axis, as in spring- beauty (Claytonia) and ^lie|)lierd"s-purse (C'apsel- la). Such an inlloresccnce is elongnled. open, and spray like. I'aniviv, a modilieution of the raceme, in which the llower-sUilks especially the lower ones, branch, bear a small cluster of Mowers, and together produce a general cluster more or less pyramidal in outline, as in the spray-like in- florescence of many grasses (as red-top). Thyrsus, a niodilication of the piuiicle, in which the llow- «rs are so congested as to form a compact pyram- idal cluster, as in the lilac and a bunch of grapes, ^'pl7.•c, a nuHlilieation of the raceme, in which the individual llowers have no stalks, but rest directly upon the elongated axis ('sessile'), as in the common plantain and many grasses (e.g. timothy). Sometimes these sessile llowers are so close together as to cover the axis com- pletely, in other cases they are more or less scat- tered along it. A spitclel is literally a small spike, but the term is applied almost exclusively to the small spicate llower-clusters which to- gether make up the gem nil spike or panicle of grasses. Anient or calkin, ])ractically the .same as a spike or raceme, but with the subtending biacts so conspicuous as to conceal the llowers until pollination, as in the pussy-willow, alder, liirch, etc., which in consequence are often called 'amentaceous' plants. iSpudix, a modification of a spike, in which the axis l)econics fleshy, as Jack- in-the-pulpit (Arisirma) and calla. In this case the fleshy spike or spadix is more or less en- veloped by a great cnsheafhing bract calleil the spathc. which is often conspicuously colored. In the calla it is waxj' white, and represents to most persons the 'flower.' This inflorescence is char- acteristic of the great family of Aroids. Corinnb, in which the stalks of the lower flowers are elon- gated in such a way as to produce a more or less flat-topjied cluster. In such a cluster the lower flowers are the outermost, and as they bloom first, the order of blooming, while really ascend- ing or acropetal as in the raceme, appears to be from the cin^umference toward the centre, or centripetal. Most of the so-called corvnibs are cymes (see below). Umbel, in which the floral axis does not elongate. The flower-stalks ap[)ear therefore to rise from the same point, like the braces of an umbrella. This also results in a flat-topped cluster, as in wild carrot, wild par- snip, etc. Since each flower-stalk is usially sub- tended by a bract, in an umbel the bracts arc thrown together in a rosette, which is called the tnvolucre. Umbels very often become compound, that is, each main stalk Cray') of the cluster bears another umlwl. so that the general umbel is composed of a collection of small ones called umbellcls. who.se involucres are called inroluceti. This inflorescence is characteristic of the great family Umbellifersp. Head, a modification of an umbel, in which the flowers are sessile (without stalks), and result in a compact, head-like clus- ter, as in sunflower, dandelion, etc. In this case also au involucre is a conspicuous feature, and in the great family Composita; the whole head with it^ numerous llowers is commonly thought to be a single lloiver. In the ci/iniise type of inflorescence the first flower appears at the cud of the axis, which therefore ceases to elongitte (hence a 'deteriin nute' inflorescence). As a consequence, tli flower-buds appear successively down the axi- hence this nietliod is called basipital or drsvcml ing. There are several modifications of the eymose type, but llie single term in mo^t common use is cj/HK, which names a llattopiH-d cluster re- sembling .1 corymb. It may be distinguished easily, how'.'vcr, by the fact that the flowers Ik>- gin to bloom in the centre (top) of the clustri and the succession is toward the circumfcrenci or centrifugal, as in elder a!id hydrangea. A ' fjlonicrulc is a cyme in which the llowers are so much crowded as to form a sort of head, as in some dogvoi)ds. INFLXnEN'ZA (It., influence), Kpioemic Ix- ruENZA, or La tiBii-ft:. An infectious disease due to a s|H'eific bacillus and characterized by great weakness and prostration, with mentjil de- pression, and generally by catarrh of the nasal ui^d respiratory pass.iges. HfSTOHY. Authentic epidemics of influenza have occurred frequently since 1173. In that year the disease spread over Italy, (iermany, and England. The next epidemics occurred in 1'239 and 1311. as far as available records show, though it is possible that the ]>estilence which devastated France in 131 1 was of another nature. In 1323. 1327, 1387, and 1403 epidemics of la gtippc certainly occurred, as well as in 1-104, 1411, 1414. and' 1427. The first pandemic of the disease re]>orted appeared in 1.510 and spread over all Kviropc. apparently arising in Africa. It was Ih-nign in character. In 1557 occurred a repetition of the ex|>erience. all Europe suflering. having been invaded by way of Asia, and spread- ing, some historians report, to America. The niortaiity from this epidemic was very large. In 1580 the second pandemic appeared, and it was characterized bv s[H-cial virulence. Epidemics followed in I5!>i. 1503. 1507. and ir.26. In 1647 the influenza s])read through the plantations of America, and in the ^^■cst Indies. Hubbard re- ports that theredied in BarbadfX'sand Saint Kitts 5000 or 0000 each. 10.58. 1075. IBSS. 1003, 1700. !7r2, 1720, and 1732 were rrrippr years. In the last-named year the American colonies sufTered. as also llie est Indies. Mexico, and Snulh AnuT- ica. Russia. Poland. Germany. Switzerland. Hol- land. F^ngUnd. Scotland. France. Spain, and Italy were attacked in al)out the order named. People upon vessels in the open sea were said to have been attncked. In 1737 and 1742-43 the dread disease reappeared. In accounts of the l.if ter epidemic the terms 'influenza' and "pripi" first appeared. In 17.58. 17(>I. 1702. 1707. 177.5. 1780. 17S1-S2. 1788-89. 1700-1800. 180203. the disease was reported in epidemic form, and from 1803 to 1830 it spread from country to cnunlrv disappearing and reappearing after short inter vnls. China is supposc<| to have suffered most in 1830-32. I'pper Asia. Europe, and North Africi being invaded in 18.33. From 1836 to 1848 it prevailed in various loc.Tlities. as also from 18.50 to 1880. In 1847-48 the influenza was pandemic, with a high mortality. The pandemic in which the present generation is most interested began