290 PBOFESSOR BABINGTON ON RUBUS IN 1891. The points which seem to require especial attention are the direction of growth of the barren stem of the year, the form of its transverse section, and its armature; also when leaves are men- tioned without any distinction, those found on that stem are intended. In the description of those leaves attention should be paid to the stalked or sessile state of the leaflets, especially the lower or outer pair ; the form of the terminal leaflet, all parts of it being considered ; and the relative length of it and its partial petiole ; and the character of its toothing. The form and structure of the panicle is also very important ; the form and direction at different stages of the sepals and their armature ; the length and direction of the stamens relatively to the pistils and their colour, and that of the petals. Colour is usually considered by botanists to be of very little value, but it seems to be important and often quite permanent in many Eubi. There is also another point concerning which I know very little, which our great masters in this study consider of value ; I mean the presence or absence of hairs on the young germens. It will be seen that many of these things can only be observed on the living plant ; it is therefore most important that they should be noted at the time when the specimen is collected. The want of this care on the part of collectors has caused exceeding difficulty in correctly naming many of their specimens which may be in most other respects well preserved. It has been well remarked by Weddell (Ann. Sci. Nat. ser. 6, ii. 856) that, "Except in a very few cases, it is impossible to dis- tinguish exactly one species from its neighbours by one single character alone." This is the case in all groups where the species are numerous and closely allied, and in such cases we are deprived of the use of analytical keys such as that prepared with so much care by Genevier. In almost all cases there are intermediate forms which are not discoverable by them. Also they require the presence of much knowledge which is often absent when the key is brought into use. I refer to such points as (1) the direction of barren growing stem of the year ; (2) the form and especially the colour of the petals ; (3) the length and direction of the stamens ; (4) the direction of the sepals both in the flower and with the fruit. The question of nomenclature is very difficult. We have been used primarily to look to the Ruhi Germannici as a great authority. But there a difficulty meets us. The descriptions and plates do not always seem to correspond. The two authors appear to have worked independently. The specimens named by Nees for Leighton have rather confused our ideas instead of clearing them. This is now more apparent since Banning and Focke have determined thirty-three out of the forty-two species of Weihe "with absolute certainty." The latter distinguished botanist has cultivated many of them, and described them with remarkable care in his Synopsis. He also holds as I do that it is not advisable, nor for the promotion of science, to drag into the light of day obscure matters which had better have been left in the shades of night. Thus names buried in little-known tracts or neglected books had better not be hunted
