LINEAE 

 161. Linum L. 



215 



544. L. catharticum L. (Herm. Muller, 'Fertilisation/ p. 147; MacLeod, 

 Bot. Jaarb. Dodonaea, Ghent, vi, 1894, pp. 238-9; Warnstorf, Verh. bot. Ver., 

 Berlin, xxxviii, 1896.) The filaments of the small white homogamous flowers are 

 fused at the base into a fleshy ring, which, as Herm. Muller explains, secretes 

 on its outer side five drops of nectar from five small, flat pits situated in the middle of 

 the filaments. The five petals are inserted into the same ring, a little higher than 

 the nectar-pits, and alternating with them. The lower halves of their edges are 

 closely applied, but their bases suddenly narrow, so as to leave a small round 

 aperture giving access to the nectar immediately above each nectar-pit. The 

 anthers are at the same level as the stigmas, but are at first remote from them, 



Fig. 65. Linum catharticum, L. (after Herm. Muller). (i) Young flower, seen from above: the 

 anthers are still remote from the stigmas. (2) The same seen obliquely from above. (3) Somewhat 

 older flower seen from above : the anthers are applied to the stigmas (4) Flower after removal of the 

 calyx to show the insertion of the petals and the position of the nectaries. (5) Stamens and stigmas in 

 the act of automatic self-pollination. (6) Sepal seen from the inner side, with a drop of nectar, 

 a, anthers ; a 1 , the united filaments ; st, stigma ; n, nectaries. 



so that insect visitors may effect either self- or cross-pollination. Failing such 

 visitors, automatic self-pollination takes place, the stamens bending more and more 

 inwards, and the flowers closing in the evening. 



Warnstorf describes the flowers as slightly protogynous, the stigmas maturing 

 before the flower opens. The pollen-grains are large, golden-yellow, spherical or 

 ellipsoidal, tuberculated, with a maximum length of 50 fi and breadth of 30-37 /*. 



Visitors. Herm. Muller saw the following. 2 nect-skg. flies, a Bombylid 

 Systoechus sulphureus Mikan in Westphalia and an Empid Empis livida Z. in 

 Thuringia. 



MacLeod observed a Syrphid and a Bombylid in the Pyrenees (Bot. Jaarb. 

 Dodonaea, Ghent, iii, 1891, p. 406). 



In Dumfriesshire, an Empid, a Muscid, and a hover-fly were recorded (Scott- 

 Elliot, 'Flora of Dumfriesshire,' p. 35). 



