BERBERIDEAE 



55 



V. ORDER BERBERIDEAE VENT. 

 29. Berberis L. 



Homogamous flowers with half-concealed nectar, arranged in dense racemes, 

 so that in spite of the relative smallness of the individual blossoms, they are very 

 conspicuous in the aggregate. The inner sides of both sepals and petals are yellow 

 in colour. Nectar is secreted by two fleshy swellings on the inner side of each 

 petal near its base, and owing to the concave shape of the corolla these are 

 tolerably well concealed. Many species possess sensitive stamens, which suddenly 

 move towards the pistil when they are touched at the base of their inner surface, 



115. B. vulgaris L. (Sprengel, 'Entd. Geh.,' pp. 203-6; Herm. Miiller, 

 'Fertilisation,' pp. 90-3, 'Weit. Beob.,' I, p. 323, 'Alpenblumen,' p. 142; Kirchner, 

 'Flora v. Stuttgart,' p. 255; Knuth, 'Grundriss d. Blutenbiol.,' ' Bloemenbiol. Bij- 

 dragen.') Sprengel, who first described the structure of the flowers, believed them 

 to be self-pollinated : ' When a stamen that has been touched by an insect applies 

 itself to the pistil, it presses the inner side of its apex which is covered with pollen 



Fig. SI. Herberts vulgaris, L. (after Herm. Miiller). I. Flower seen rom above: a, the three 

 large inner sepals, which by their size and colour serve to attract insects ; b, outer, and V, inner petals; 

 c, nectaries : d, filaments ; e, stigma. 2. Position of the stamens after moving inwards towards the 

 pistil. 3. Petal with its two thick, fleshy, orange-red nectaries (c). 4-7. Stamens in various stages of 

 dehiscence, erection, and rotation of the anther-valves, seen from the outer side. 4. Stamen with the anther- 

 lobes still closed. 5. The outer wall of the right anther-lobe has become free below, so as to form 

 a valve, of which the free end is beginning to turn upwards with the pollen attached to it. 6. Both valves 

 have nearly completed their upward movement 7. Both valves have turned in such a way that the 



pollen-masses are directed towards the middle of the flower. 7 b. Inner side of a stamen in this stage. 



closely to the stigma, and this being moist, a part of the pollen must adhere to it. 

 The stigma is thus gradually pollinated all round, and the ovary is fertilized.' 



Hermann Miiller proved this view to be erroneous, and explained the flower 

 mechanism as an adaptation to cross-pollination. 



The flowers are either horizontal or hang obliquely downwards (not vertically 

 downwards as described and figured by Sprengel). They are, therefore as Hermann 

 Miiller emphasizes not fully sheltered by their position from the entry of rain, 

 though a tolerable amount of protection is afforded by the three inner concave 



