34 INTRODUCTION 



II. Autogamy. 



Kerner ('Nat. Hist. PI.,' Eng.Ed. i, II, pp. 331-401) has treated at length the various 

 kinds of Autogamy, and especially distinguishes between the following categories : 



1. The anthers lie close to the stigmas, covering these when they open. This 

 occurs more especially in small annual plants, such as Centunculus minimus, species 

 of Drosera, Lepidium ruderale, Geranium pusillum, Lithospermum arvense, and others, 

 and also in a number of Liliaceae, as e. g. some species of Fritillaria, Narcissus, 

 Trillium, Uvularia, Crocus. 



2. In pendulous flowers with anthers united into a cone, the filaments relax 

 when the flower is nearly mature, so that the loculi are no longer so closely 

 apposed, and the mealy pollen falls on the underlying stigmas; e.g. Galanthus, 

 Soldanella, Dodecatheon. 



3. In erect flowers, when the walls of the anthers contract, pollen falls on 

 the stigma, which lies vertically beneath : Narthecium, Tofieldia. 



4. In erect funnel-shaped flowers, the pollen glides along the smooth inner 

 wall of the corolla to the deeply seated stigma: Syringa. 



5. During flowering the filaments elongate, so that the anthers, which are to 

 begin with at a lower level than the stigma, finally reach the same level, and 

 pollinate it: Adoxa Moschatellina, species of Scleranthus, Paederota Bonarota, 

 many Cruciferae, species of Saxifraga, small-flowered species of Epilobium and 

 Geranium, Ipomaea purpurea, Agrostemma Githago, Saponaria Vaccaria, Silene 

 conica. 



6. The straight filaments are at first directed outwards, keeping the anthers 

 away from the stigma, so that self-pollination is not possible ; later on the stamens 

 incline towards the middle of the flower, so that the pollen-covered anther-lobes 

 touch the stigma, and pollinate it : Azalea procumbens, Draba aizoides, numerous 

 Saxifragaceae, Alsineae, Cruciferae, Hypericum perforatum, Oxalis stricta, Orni- 

 thogalum umbellatum, Paris quadrifolia, species of Scilla, Chelidonium, Samolus 

 Valerandi, species of Androsace, Lysimachia nemorum, Swertia perennis and 

 punctata. 



7. The filaments are from the first inwardly curved; later on they incline 

 still further inwards, till they either come in contact with the stigma, or are 

 perpendicularly above and able to shower down pollen upon it : numerous Com- 

 positae, species of Galium and Cuscuta, Circaea alpina, Agrimonia Eupatoria, 

 small-flowered species of Sedum, Opuntia, species of Rosa, Hepatica triloba; 

 species of Ranunculus, Gypsophila, and Saxifraga; Cuphea, Nicandra. 



8. The style at first projects beyond the anthers, but shortens later on, so 

 that ultimately the anthers (still covered with pollen) come into contact with the 

 stigma: species of Cereus, Echinopsis, and Mammillaria. 



9. Autogamy results from the lengthening of the ovary or of the style : 

 Epimedium alpinum, Sinapis arvensis, Atragene alpina, Clematis integrifolia, 

 Alchemilla vulgaris. 



10. Autogamy results from inclination of the style, which, however, remains 

 straight : CoUinsonia canadensis. 



11. Autogamy results from bending of the style, so that the stigma is either 

 brought into immediate contact with the pollen-covered anthers, or assumes such 



i 



