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A statistical analysis was made of the 3600 species of plants known to contain alkaloids and their 2000 alkaloids to determine distribution by families, diversity of occurrence of individual alkaloids, how the size of the alkaloids (number of carbons) in species may be correlated with habit, habitat, family and geographic location. The categories used for comparison were woody, herbaceous, temperate, tropical, monocot, dicot and native to Australia. Woody-temperate species have larger alkaloids than herbaceous-temperate. All woody, including both temperate and tropical, have larger alkaloids than all herbaceous. In both herbaceous and woody, the strictly tropical and temperate species have larger alkaloids than the sub-tropical and the warm-temperate. Within the herbaceous species, monocot-temperate have much larger alkaloids than dieot-temperate, but those of the dicot-tropical are larger than the monocot-tropical. In families containing 60 or more kinds of alkaloids, there is a tendency for the number of alkaloids having the same number of carbons to follow a normal distribution curve, or, so to speak, for the family to specialize in aklaloids of a given size. The peak, or the size representing the greatest number of alkaloids, is characteristic of the family and varies from 15 to 27 carbons. Caffeine occurs in the largest number of families (14), lycorine in the largest number of genera (30) and berberinc in the largest number of species (89).

In the very extensive literature in the Chinese language, there is a vast store of material relevant to economic plants. The Chinese, a traditionally agrarian and at the same time utilitarian people, are also historically minded. They have recorded over 30 centuries much of their knowledge about plants, their occurrence, introduction, cultivation, variation, and utilization. The Chinese literature has frequently been pointed out as the best source material for studies on the domestication and utilization of cultivated plants. Many of our present important crop plants originated in China. A large number of cultivated plants of extra-Chinese origin had also been introduced into China in ancient and medieval times. This paper is an attempt to identify the principal vegetables cultivated in ancient China and to trace the fate of these crops during the course of the history. As the literature on plants in China is scattered among widely different sources, an exhaustive or definitive study is not here intended. Fortunately for our purpose, there is still preserved a complete treatise on agriculture more or less intact, the Ch'i-min-yao-shu (Essential arts for the people), by Chia Ssu-hsieh of the Later Huei of the Northern Dynasties. This book was produced in the late 5th or early 6th Century and is probably the oldest complete treatise on agriculture extant in any language. While this work does not describe the most ancient conditions of agriculture in China existing around 3,000 years ago, it does give us a full record of the situation of crop plants and agricultural practices in northern China along the Yellow River Valley about fourteen centuries ago. This is the region where the ancient Chinese civilization originated and developed in the earlier times. This work has recently been translated into modern Chinese and extensively annotated and commented on by Shih (6). He

From the above, it can be seen that, although with only limited data, a study of general occurrence of alkaloids seems to indicate certain correlation with phylogeny. Within the dicotyledons, there is a high incidence of alkaloid occurrence in the morphologically primitive Magnoliales–Ranales complex and related groups, a lower incidence in various phylogenetically intermediate groups and a progression of high incidence in all of the phylogenetically advanced but unrelated groups. Notably, the generally wind–pollinated “amentiferous” families, as well as the wholly aquatic families, are either alkaloid–absent or show very low incidence. High incidence of alkaloid occurrence appears as a general character, for some families or orders. In some families, such as Ranunculaceae, Berberidaceae, Menispermaceae, Piperaceae, Cactaceae, Papaveraceae, and Gentianaceae, alkaloids occur in over 90% of the species tested. In many others, there is also a high, though less pronounced, percentage. On the other hand, in certain families such as Fagaceae, Betulacae, Casuarinaceae, and Juglandaceae the alkaloid occurrence is almost zero. Thus, the occurrence of alkaloids can be treated as a general family characteristic. At the ordinal level, high or low incidence may appear uniformly in all component families of a single order or sometimes pronouncedly in one of the component families. As a general characteristic, incidence of alkaloid occurrence appears to be a useful one for phylogenetic analysis at the family or order levels. Even though, with the limited amount of data available, it is futile to speculate on the significance of alkaloid incidence among the dicotyledons (other than to point out the seemingly definite pattern of correlation with the phylogenetic scale), it may be worthwhile to point out the notable absence or near absence of alkaloids among the “amentiferous” families (which are windpollinated). Further research along the lines correlating pollination and specific pollinators with distribution and structure of alkaloids, together with the morphology, taxonomy and phylogeny of the flowering plants, will be most desirable and may yield interesting results.

Although Cannabis is generally believed to be of Asiatic origin, within this vast geographical area, there is no general agreement as to where the domestication really came about. Alphonse de Candolle (1884), the first authority on the origin of cultivated plants, ascribed a very extensive range to the plant. He asserted that "the species has been found wild, beyond a doubt, to the south of the Caspian Sea, near the Irtysch, in the desert of Kirghiz, beyond Lake Baikal in Dahuria (government of Irlkutsch). Authors mention it throughout southern and central Russia and to the south of the Caucasus, but its wild nature is here less certain, seeing that these are populous countries, and that the seeds of the hemp are easily diffused from gardens. The antiquity of the cultivation of hemp in China leads me to believe that its area extends further to the east, although this has not yet been proved by botanists. " Later workers, mostly working on field collections, either have accepted this very general and extensive area, or favor specific regions, such as the Himalayas, central Asia, India, Pakistan or China (Vavilov, 1926; Zhukovskii, 1962). It is a difficult problem to differentiate truly wild plants from spontaneous, escaped or semicultivated plants. There still remains much to be done to clarify the systematics of Cannabis. Moreover, in the case of Cannabis, which has been associated with man for so long, botanical studies alone are inadequate to ascertain the origin of cultivation. As one author states (Schultes, 1972), "It would seem that historical and ethnobotanical evidence

No doubt chemists and botanists will continue to look for further alkaloidbearing plants and to isolate and study the contained alkaloids. Hence perhaps we are justified in trying to deduce from the above analyses where the best hunting might be. The bacteria would be a likely place to look for new types of alkaloids, partly because their presence has been indicated by qualitative tests in at least 21 species, and partly because these alka loids are likely to be of different types from those in the other major plant taxa. Seeds should be assiduously studied. Alkaloids are already known to occur in the seeds of some 600 species. If alkaloids of interest were found, seeds would be a more satisfactory source than, say, roots. Where collection of material from a particular family is feasible the following families could well be considered, because of the size of the family and the large number of species already known by qualitative means to contain alkaloids: Verbenaceae, Caryophyllaceae, Labiatae.