Reports of the Survey. Botanical Volume 3
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1899 edition. Excerpt: ...of herbs best developed in the tropics and very remarkable for marvelously perfect adaptation to the submerged life. The plant-body of many of the riverweeds resembles that of an alga, the leaves being poorly distinguished from the stem on which they are borne. The flowers and fruits are produced entirely under water and are surrounded by involucres resembling the spathes of the arum family. In the Minnesota variety--the only one common in North America--the flowers boundary, in the Granite lake rapids, at Minnehaha falls and at Lake Pepin. The most interesting thing about the riverweed is its entire abandonment of terrestrial methods of flower-production and pollination. While pondweeds are compelled to lift their spikes of flowers above the surface of the water to accommodate themselves to the persistence of ancient methods of wind-distribution in vogue during the days when their ancestors were dwellers on the land, the riverweeds have freed themselves from this necessity and have the ability to maintain themselves quite submerged in deep water, as if they were algae. Some other varieties of flowering plants flower under the are sessile, there is no perianth and there are two stamens united together at the base. The fruitrudiment is ovoid, with two short stigmas. The general appearance of the plant is that of a dense tuft of finely divided leaves attached to the stones at the bottom of the water. The flowers are small and easily recognized by the two partly fused stamens, standing like a little fork beside the ovary. In the fruit arise a number of small seeds with straight embryos and without albumen. The riverweed has been collected in Minnesota on the International water, as, for example, the marine eel-grass, so common along...
- 189 x 246 x 10mm | 340g
- 13 Sep 2013
- United States
- black & white illustrations