538 GYMNOSPERMAE 



Centralbl., Cassel, xxxiii, 1888, p. 91) found the relative numbers of male and female 

 stocks varying greatly according to the nature of the soil ; to 100 male plants he 

 found 63 female ones in a light fir-wood ; while the proportion was 100 : 143 on the 

 poor sandy soil of the Dovrefjeld. 



3090. J. rigida Sieb. et Zucc. (Strasburger, op. cit.) — This species possesses 

 the same flower mechanism as the last one. 



3091. J. Sabina L. — As Nos. 3089 and 3090. 



1030. Pinus L. 



3092. P. sylvestris L. (Sprengel, 'Entd. Geh.,' pp. 432-3; Strasburger, 

 op. cit., pp. 251-3.) — This species is monoecious. The young female cones are 

 situated close to the tip of the youngest shoot, before the unfolding of the double 

 needles ; they are arranged singly or several together in a vertical position, so that 

 they are accessible from all sides. The ovuliferous scales possess a projecting, 

 elongated keel in the middle and diverge a little during anthesis, in consequence of 

 the lengthening of the axis of the cone. Two ovules are situated, one to the right 

 and one to the left, at the base of every scale, and that margin of their micropyle 

 which is turned towards the axis has now grown into two long, lateral processes, 

 formed of colourless, transparent cells turgid with fluid, and secreting abundantly. 

 If the pollen-grains, which are scattered in large dust-clouds by the lightest breeze, 

 fall on the young cones they slip down the vertical scales on each side of the keel, 

 reach the fluid-secreting processes, and are gradually drawn to the ovules. The keel 

 of the scale causes the pollen-grains to slip down on the smooth, dry surface and 

 easily reach the ovules. Those which fail to do this fall into one of the passages 

 running right and left round the axis in consequence of the narrow insertion of the 

 scales, and may then pollinate more deeply-placed ovules. After pollination has been 

 effected the scales thicken rapidly and close up together, the resin secreted at their 

 edges helping them to adhere. The keel does not develop further, but dries 

 gradually. The original beautiful brownish-red colour disappears, and the cone 

 gradually becomes pendulous. The micropyle still remains open for a long time, 

 and is only closed much later by the extensive thickening of its edges. Kerner says 

 that the pollen on being scattered is first deposited in two shallow grooves on the 

 back of the anther next below, whence it is then removed by the wind. 



Visitors. — Redtenbacher records the following beetles. — 



(Austria) — [a) Alleculidae : i. Omophlus amerinae Cur/, {i) Telephoridae : 

 2. Dasytes obscurus GyH.; 3. Haplocnemus pini Red/.; 4. H. pini Red/., var. 

 serratus Red/. ; 5. H. tarsalis Sahib. (Vienna) — (c) Curculionidae : 6. Brachonyx 

 indigena Z^i5j-/. ; 7. Magdalis violacea Z. 



3093. P. Pumilio Haenke. (Strasburger, op. cit.) — Strasburger says that this 

 species possesses exactly the same pollination mechanism as the last one. 



3094. P. Pinaster Ait., and 3095. P. rigida Mill. — These species agree with 

 the two last. 



3096. P. resinosa Ait. — This species is similar in all respects, except that the 

 keel is directed inwards. (Strasburger, op. cit., foot-note.) 



