. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. THE ORIGIN OF " ZYGOMORPHISM. 121 plants, as Narcissus Corbwlaria. In Anagallis arvensis and Lycium barharum there is nothing bat an obliquity in the style observable. In all the flowers which tend to show irregularities the rule is that the corolla-limb stands in a vertical plane, so that the flowers are visited from the front. This I take, as mentioned above, to be generally a primaiy necessity for bringing about irregularities of all kinds. There are some campanulate and pendulous flowers w
. The origin of floral structures : through insect and other agencies. Plants; Flowers; Flowers. THE ORIGIN OF " ZYGOMORPHISM. 121 plants, as Narcissus Corbwlaria. In Anagallis arvensis and Lycium barharum there is nothing bat an obliquity in the style observable. In all the flowers which tend to show irregularities the rule is that the corolla-limb stands in a vertical plane, so that the flowers are visited from the front. This I take, as mentioned above, to be generally a primaiy necessity for bringing about irregularities of all kinds. There are some campanulate and pendulous flowers where irregularity occurs in the lengths of the filaments or the size of the anthers. Thus, I have observed great fluctuations in the stamens of Narcissus cernuus : some of these I have illustrated in Fig. 37. I noticed that a peduncle always bore the same form in every flower of its umbel. There were mostly three flowers in each, as of a, h, and d; one specimen of a and one of e had only a single flower; and one of c had two flowers. In a, b, c, d, the three short stamens, as well as the three long ones, were all of the same height, respectively; but in e one of the shorter set was taller than the rest. Similar flactaations are not at all uncommon in cultivated heterostyled plants, as Primroses; as will be alluded to again in discussing the conditions of heterostylism. In Fritillaria Meleagris, though no irregularity occurs in the perianth leaves, it often appears in the androecium, and is more especially obsei-vable in the lengths of the anthers. This would seem, therefore, to be another instance of incipient change. Calluna vulgaris is likewise just commencing to be 13. Fig. 37.—yarcissus Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Henslow, George, 1835-1925. New York : Appleton
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