microphyllus reach even higher, probably setting the altitudinal record for the family at 4800 m. Several species are associated with freshwater, such as Lobelia dortmanna, an isoetid common in oligotrophic lakes in the boreal zone of North America and Europe, and Howellia aquatilis, an elodeid growing in ponds in SW North America. There is usually abundant, white latex, but occasionally the exudate is clear and/or very sparse, as in Jasione. Tubers occur in several genera, e.g. Cyphia. Leaves are often alternate, more rarely opposite (e. g. Codonopsis) or whorled (Ostrowskia). They are simple (Petromarula one of very few exceptions) entire (repeatedly divided in spp. of Cyanea), but often with dentate margin. Stipules are absent. Inflorescences are quite diverse, including both cymose and racemose types. In Jasione they are strongly condensed and resemble asteraceous capitula. In a few species, e. g. Cyananthus lobatus, flowers are solitary. Flowers are bisexual (dioecious in Dialypetalum) and protandrous. Petals are fused into a corolla with 3 to 8 lobes. It may be bell- or star-shaped in subfamily Campanuloideae, while tubular and bilaterally symmetric in most Lobelioideae. Blue of various shades is the most common petal colour, but purple, red, pink, orange, yellow, white, and green also occur. The corolla may be down to 1 mm wide and long in some species of Wahlenbergia. At the other extreme, it reaches a width of 15 cm in Ostrowskia. Stamens are equal in number to, and alternating with the petals. Anthers may be fused into a tube, as in all species of Lobelioideae and some Campanuloideae (e.g. Symphyandra) Within the family pollen grains are often tricolporate, less commonly triporate, tricolpate, or pantoporate. Carpel number is usually 2, 3 or 5 (8 in Ostrowskia), and corresponds to the number of stigmatic lobes. The style is in various ways involved in the "presentation" of the pollen, as in several other families of the order Asterales. In Lobelioideae, pollen is, already in the bud stage, released into the tube formed by the anthers. During flowering, it is pushed up by the elongating style and "presented" to visiting pollinators at the apex of the tube, a mechanism described as a pollen pump. The style eventually protrudes through the anther tube, and becomes receptive to pollen. In Campanuloideae, the pollen is instead packed between hairs on the style, gradually being released as the hairs invaginate. Subsequently, the stigmatic lobes unfold, and become receptive.