RHODOPHYCEÆ                                    1609                                                        RIBBON

drons have been cultivated as garden-plants with great success. Many hybrid forms have beautiful and conspicuous flowers, without having lost the hardiness of the native species. The plants of the genus flourish in a moist but well-drained soil, preferably somewhat of the nature of vegetable mould. Thickets of rhododendron maximum are among the beauties of the Alleghanies, some having carmine, others lilac-colored, others purple flowers.

Rhodophyceæ {ro'do-fts'ê-è), plants commonly known as the red algæ. _ The red color is due to the presence of a pigment in addition to the ordinary chlorophyll which belongs to all algæ. They mostly are marine forms and are anchored by holdfasts, belonging to the deepest waters in which algæ grow. Their bodies are much more delicate than those of the brown algæ or kelps, their graceful forms, delicate texture and brightly tinted bodies (shades of red, violet, dark purple and reddish brown) making them very attractive. They show the greatest variety of forms, branching filaments, ribbons and filmy plates prevailing, sometimes branching very profusely and delicately and resembling mosses of fine texture. They are among the most prized souvenirs of a visit to the seashore. Red algæ are very peculiar both in asexual and in sexual reproduction. Every sporangium contains just four asexual spores, and, contrary to the usual alga habit, these spores have no cilia or power of motion. Since they are always produced in fours, they are called tetraspores. The female sex-organ also is very peculiar. In the ordinary algæ the oogonium consists of a single, large, spherical cell. Among the red algæ, however, this spherical cell is transformed into a flask-like body, with bulbous base and an elongated, almost hairlike neck. This female organ, on account of its peculiarities, is often called by a special name, carpogonium, the tubular hair-like process being called the trichogyne. The male cells come in contact with the trichogyne in the process of fertilization.

Rhone {ran), the only important French river which falls into the Mediterranean, rises in the Swiss Alps not far from the

sources of the Rhine, its entire length being about 500 miles. There is sufficient depth for good-sized vessels from Lyons southward, but, on account of the rapidity of the current and the shifting of sand-bars, navigation is difficult and at times impossible. On account of these obstructions, which are greatest near the mouths of the river, communication with the Mediterranean is in great part dependent upon the canals which connect the Rhône with the Rhine, the Seine and other rivers.

Rhu'barb, species of Rheum, a genus of the buckwheat family. Common garden rhubarb or pie-plant is R. rhaponticum, native to the Old World. The genus is very closely related to the common docks, many of which resemble the rhubarb in habit.

Ribault (rê'bo'), Jean, a French Huguenot, was born at Dieppe about 1520. He was sent by Admiral Coligni to establish a colony of French Protestants in North America. He set sail with an advance party on February 18, 1562. Having built a fortress at Port Royal Harbor, he left a garrison of 30 men in charge and returned to France. He found the country in the throes of civil war and was unable to return or to send provisions. After enduring great sufferings the men abandoned the fort and attempted to return to France, in an old vessel which managed to hold together for a time. When it was about ready to collapse, the men fortunately were picked up by an English cruiser and taken to London. In 1564 Ribault was made governor of a proposed colony in Florida and René de Laudoniere was sent out with colonists. In May of 1565 Ribault again sailed, this time with seven vessels and 300 men. He arrived on August 28, and shortly afterward some Spanish colonists under Menendez de Avilez made an attack upon his ships. He set out to retaliate, but his vessels were wrecked by a storm and he was obilged to attempt to return to the fort overland. In the meantime the Spaniards had marched overland, captured the fort and murdered all the occupants, except a few who made their escape in a couple of old vessels. Ribault and his men surrendered to the Spaniards under assurances of safety, but in October of 1565 they were put to the sword.

Rib'bon, a narrow band or strip of woven silk. Ribbons have been made an important article of commerce only during the last two centuries, the chief seats of their manufacture being Etienne, France; Basel, Switzerland; and Coventry, England. Of the names which indicate the kind of groundwork, grosgrain is a ribbed silk, plush a velvety or piled surface, satin a smooth, polished surface etc. ; and there are various mixtures of these, making an almost infinite variety of decorative effects both in color and weaving.

Description images/pp0512 1

A red alga (A), showing the female organ (o) with its trichogyne (i). the male cells (s) and the resulting spore case (JB, C).