Marshall Avery Howe

“ Our experiments in germinating the spores of Riella affinis have been more successful than those with the spores of Riella Americana, though they were not begun until December, 1902, five and a half years from the date of collection of the specimens. More than half of the spores experimented with germinated in a few days by being placed on a piece of wet filter-paper in a glass dish kept in a moist chamber at ordinary living-room temperatures. The germ-tube in practically all cases emerges, as in R. Americana, from the outer or more spiny face of the spore, usually near its middle. ”

“ The genus Riella occupies a unique position among the Hepaticae. The striking peculiarities of its gametophytic phase have attracted the attention of such morphologists as Hofmeister, Leitgeb, and Goebel, in addition to the interest excited among those who have devoted themselves more exclusively to a study of the systematic relations of the Hepaticae. Riella helicophylla, an Algerian species, is alluded to in some of the standard botanical text-books as being peculiar among the liverworts in having a leaf-like lamina or wing disposed spirally in relation to the axis or stem. ”

“ The new cells formed on the upper or distal side of the growing point now contribute to the growth of the unistratose wing, which is dorsal in position. The new cells formed on the lower or proximal side of the growing point go to constitute the multistratose stem, which is ventral in position. ”

“ In considering the more technical aspects of Professor Underwood's botanical work, one is impressed by his instincts for collecting and systematizing, by his ability to express results in a terse, vigorous, synoptical form, and by the importance which he attached to the study of living plants in their natural surroundings as distinguished from the study of their mummified remains in herbaria. ”

“ If two growing points on opposite margins of a young shoot persist, a double or twin plant is formed, the two branches of the axis bearing a single continuous dorsal wing. If, however, only one growing point persists, the plant or branch is apparently one-sided, with stem on one side and wing on the other, though in reality the wing is dorsal and the stem ventral.
On account of the absence of elaters, Riella was at first placed with the Ricciaceae, together with Sphaerocarpus, in which, likewise, elaters are not developed. ”

“ And his personal acquaintance with plants was remarkably wide even outside of the ferns, the Hepaticae, and the fungi, the groups in which he found his special fields for research. Accordingly, his outlook upon botanical science as a whole had a breadth and sanity that is all too rare in the men that have been schooled in an age of more extreme specialization. ”

“ The larger-celled part, derived from the apex or distal end of the initial trichome, becomes at about this time more than one cell thick in its middle and terminal regions and shows papilliform outgrowths, the beginnings of the root-hairs. The smaller-celled portion derived from the base or proximal end of the initial trichome remains only one cell thick except in the isthmus of constriction where it finally, in part at least, becomes two or more cells thick. F. 16 shows a well-developed gemma inverted as regards its original relations to the axis of the gametophyte. ”

“ The desirability or even the necessity of such a first-hand acquaintance with the living plants in order to gain any adequate notion of their affinities is sufficiently apparent nowadays as regards any particular group, but is perhaps especially obvious in connection with the tropical tree-ferns, species of which, in some cases, have unfortunately been described from small fragments of the dried leaves. ”

“ In describing Riella Paulsenii, the first species of the genus known to occur outside of the Mediterranean region, Porsild expresses the surmise that the distribution of the genus may prove to be still more widely extended, which is well verified by the known existence at the present time of three specimens of Riella collected within the boundaries of the United States. ”

“ The basal cells afterward grow out and divide in such a way as to give the body a free margin throughout its periphery, though it remains attached to the axis for a considerable time by a single cell on its proximal surface. ”

“ His work as a teacher of college students was not confined to exclusively botanical lines until he had reached nearly middle age. In his earlier manhood he not only taught geology, zoölogy and chemistry, in addition to botany, but also published several papers dealing with geological, zoölogical, and biological subjects. ”

“ Our specimens of R. affinis are prostrate and more or less entangled with mud and are so delicate and fragile that it is quite possible that the measurements in the above description may fail to do full justice to the height of the plant. It may be remarked that in occasional capsules the spores though showing a well-developed brown coloration have short spines or papillae much like those of R. Cossoniana; such spores are always smaller than is normal for the species and are probably immature or else have ripened under abnormal conditions. ”

“ In his several visits to Europe, he had seen and examined the materials from which most of the endemic American species of ferns were originally described, in so far as such materials are preserved, and also many foreign types with which American specimens had been identified — sometimes erroneously— by the earlier writers. ”

“ The forms assumed by the young gametophytes are extremely varied and are doubtless determined to a considerable extent by the conditions of illumination, though no exact investigations were undertaken to demonstrate the influence of light in this matter. ”