Over the last hundred years many cacti have been described, not by expert biologists, but by laymen, many of them using terms which are not a hundred percent correct. It can not be our task, to correct the errors in the descriptions and make them more comparable. We have to leave the texts of the descriptions as they were formulated by the authors. For example F. Ritter (1979) used the still common expression "Stacheln" (= spines) instead of "Dornen". Secondly the measurement of the style by Ritter should be reduced by the length of the stigma lobes, whose value Ritter always added. Also in the inter-areolar distance Ritter always used the bare distance, whereas other authors measure from center to center of the areoles.

Until recently the term "Petalen" (= petals) has been used instead of "Tepalen" (= tepals) for the Perianth segments.

F. Ritter uses the abbreviation "Krbl." with the explanation: Kronblätter: (Hüllblätter, Petalen) (= Sepals, Petals). He also used the German expression "Blütenröhre" (= floral tube) (or "Röhre" (= tube) for short) for Receptaculum (= Receptacle).

The height of insertion of the filaments in the tube wall is an important characteristic, used to divide the Notocacti into sections. F. Ritter saw the significance of this characteristic which BUXBAUM first correctly recognized. The differences in the flower construction between the sections (subgenera by Buxbaum) Notocactus and Neonotocactus correspond namely to the flower opening at certain times in the day and seed structure features. The section Neonotocactus shows in this relatively little kinship to Parodia.

We also sometimes find in the literature the term Staubblätter used for Stamina (= stamens).

After analysis of the first descriptions we can see that with time more details of the seed characteristics are listed. The first descriptions of 170 years ago often only gave the flower colour. The mostly yellow flower colour is however also a problem in the present time. What is the difference between lemon yellow, sulphur yellow, canary yellow, yolk yellow etc.? Even comparisons with standardized color plates only give good results if the different locations are under the same lighting conditions. Unfortunately plants of a population under the same cultural conditions sometimes produce flowers differing greatly in the tone of yellow. It could even be documented, that an individual produces intensely yellow colored flowers and in the following year even brighter flowers.

Also the measurements in millimeters or centimeters for certain flower parts should be treated with caution. The size of the flower and with it also almost every flower part increases in the days following the first opening. The linear measures can increase by up to 25 percent.

We should then always give more detail in the descriptions, if the plants are only distributed lightly in our collections. This counts for some taxa which F. Ritter described in 1979, but also for others, in which we suppose synonymy or very close kinship to other taxa.