Abstract.Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from •3.2 to •46 days, while those for later-flowering species range from -1-3.1 to -1-10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (Tf^in).

Campanulaceae (excluding Lobeliaceae) in North America comprise four genera and 35 species of annual, biennial, and perennial herbs. Generic and specific circumscriptions have been treated variously, and studies of seeds have been few and limited. In this study, seeds of all but one of the native North American species and of selected Eurasian putative relatives were examined with the light and scanning electron microscope. Characteristics of the seeds and their surface cells are described and compared. The seed-coat morphology was found to be relatively uniform, but there are recognizable generic patterns and a number of distinctive individual species. Seeds of Campanula americana, C. divaricata, and the other eastern species of Campanula are each distinctive and do not show the relative uniformity seen within Githopsis, Triodanis, Heterocodon. and the western species of Campanula. Seeds of the recently rediscovered C. robinsiae and of the wide-ranging C aparinoides are highly distinctive and would appear to set each of these species apart within the genus. However in Triodanis, T. texana stands apart. Seeds oi Campanula reverchonii resemble those of Triodanis colorasigni coat sculpturing and ornamentation is given.The Campanulaceae, in the strict sense (ex-Australia and South Africa. Campanula, the eluding Lobeliaceae), are a worldwide family of northern counterpart, is the largest genus of the 35 to 40 genera and perhaps 800 species. Esti-family, comprising some 300 species. It is conmates of the number of species have ranged from fined to the north temperate zone, with its center 600 to 1,000 (Avetisian, 1967; Gadella, 1974; of diversity in Eurasia. Only 23 species occur in Kovanda, 1978). The species are largely peren-North America (Shetler, 1963; Heckard, 1969; nial herbs, but some are annuals, biennials, or Morin, 1980). Three-fourths of these are narrow even small shrubs. The family is confined mainly endemics. Nearly half (11 spp.) of the North to north and south temperate regions, being re-American species occurs in the Califomia Floplaced in tropical and subtropical regions by the ristic Province, and, of these, seven species are endemic there. The family Campanulaceae is of similar size Lobeliaceae. Only Wahlenbergia, with possibly 100 species or more (Thulin, 1975; Carolin, pers. comm., 1981), is well developed in, and in fact and diversity in Europe and Soviet Eurasia. F/om restricted to, south temperate regions, especially Europaea (Tutin, editor, 1 976) records 1 3 genera 1 Lehlonen, M.-J. Mann, S. Wiser, and W. Brown 1980-1 the support of the Smithsonian Institution.

Summary The literature on the unique pollen‐collecting hairs of Campanula (Campanulaceae) is reviewed as background for new pollination studies, with particular reference to the nature and function of the collecting‐hair mechanism in the breeding system. The main features of the floral mechanism, including the pronounced dichogamy (protandry) and insect adaptation, were first described and depicted accurately by Sprengel in 1793, although pollination observations date back at least to Linnaeus in 1738. Numerous other workers have since added details but little that is basically new to our knowledge of the floral mechanism. Brief reference is made to some of the significant contributions to cytology, cytogenetics, and pollen morphology in recent years. Campanula is basically allogamous, although cases of limited autogamy are known. Experimental studies have shown that campanulas range from complete self‐sterility to complete self‐compatibility, but self‐fertilization usually is accomplished only with difficulty under experimental conditions, and there is little evidence of spontaneous self‐pollination in nature. The pollen is presented from the hairs on the style, which collect the pollen from the anthers while in the bud. The hairs have been known since 1839 to possess the unusual capacity to retract into the style, but the adaptive significance of this mechanism has yet to be explained satisfactorily. The collecting hairs, since before they were known to invaginate, have been interpreted by some investigators as part of a mechanism either to effect fertilization directly through the style without the stigmas or as a back‐up to insure autogamy when cross‐pollination breaks down. Although little evidence exists to support either view, there is still no definitive explanation of their function in the breeding system. Among campanulaceous families, the genera of the Campanulaceae s.str. are believed to have the least advanced (“naked”) form of stylar pollen presentation.

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