PLATE III.— CONIFERS— Female Organs. 



(Figs. 2, 8, and 9 from Jkxlet-Port.) 



The Female Organs are the well-known Fir-cones. Fertilisation takes place by the pollen being carried by the wind to a naked ovule; 

 and to assist in this action various expedients are resorted to. The pollen is produced in large quantities, thus allowing for a deal of 

 waste, each pollen-grain has two wing-like expansions to expose a greater surface to the wind, and the needle-shaped foliage-leaves permit 

 ready access of the pollen to the cones. The opening of the micropyle is also filled with a fluid secretion which holds the pollen-grain 

 alighting on it, and as this dries up the pollen-grain gradually slips down, till it reaches the spot where the work of fertilisation begins. 



The ripening of the cone in Pimis is slow. During the first summer the pollen-tube has grown but a short distance into the 

 nucellus. The scales of the cone close together, as in Fig. i, b, and, there is no further progress, till next summer, when the pollen-tube 

 reaches the embryo-sac and fertilises the central cells of the archegonia. Then, at the beginning of the third summer, the dry woody 

 scales separate, as in Fig. 5, and the winged seeds are ready to be scattered, to build up in future the same structures as those from 

 which they were derived. 



Flower — 



Fig. 1. (a.) Young Female Cone, as in May, upright and situated in the axil of a bract like one of the rudimentary branches. 

 (6.) Previous year's cone hanging, with scales firmly closed to protect the ovules. 

 Ripe cone in Fig. 5. 



Fig. 2. Young Female Cone enlarged, showing the beaked, open scales. 



Diagram I. — The Ovule-bearing scale in Pinus is situated in the axil of a Bract (too small to be seen in Fig. 2), and the arrange 

 ment of the fibro-vascular bundles in each shows that the two have their corresponding faces turned towards 

 each other. 

 Ovule consisting of a central Nucellus enclosed in a Coat which leaves a small opening called the Micropyle 

 leading into the Nucellus. 



The Female Cone is variously regarded as equivalent to a single flower — like the male cone — or to an aggregation of 

 flowers forming an Inflorescence. Taking a Flower in its simplest expression to be a modified axis bearing modified 

 lateral appendages for reproductive purposes, then if the bract be regarded as a Carpellary leaf (as is sometimes done), 

 and the scale as the placenta to which the ovules are attached, the whole cone will constitute a Flower ; but, if on the 

 other hand, as many suppose, the ovule-bearing scale represents a reduced branch, then the primary axis of the cone 

 bears secondary axes, and such an assemblage must be considered as an Iiiflorescetice. So instead of the violent sup- 

 position of one leaf in the axil of another, there is a single leaf representing a reduced branch, and the first leaf of the 

 branch is, as it should be, opposite to the bract from which it arises. 



Diagram II. — The Ovule-bearing scale and Bract are united in Cupressus, as shown by the double fibro-vascular bundle, and the 



inner portions of each bundle being contiguous, shows that the two corresponding faces are opposite to each 



other. The Ovule is thus borne upon the dorsal surface of the leaf, i.e., the surface originally turned away from 



the axis bearing it. 



Ovules may occur singly, as in Yew and Araucaria ; in pairs, as in Pines and Firs, Larches and Spruces ; or in 



groups, as in Cypress. 



Fig. 3. Embed Female Flower of Yew in paraffin, and make longitudinal section. 

 Integument, single. 



Arillus, supposed to represent outer Integument 

 Nucellus, a mass of cellular tissue, at first without any integument 

 Embryo-sac, at first a single cell (May), then cellular tissue formed in it by free cell-formation, and from that 



Endosperm the Secondary Embryo-sacs are gradually derived (June). 



The Yew bears male and female flowers on different trees, and the male plants are apparently the more numerous, 

 thus ensuring an abundant supply of pollen. 



The growing point of the primary axis is thrust aside, and the flower is apparently terminal. The flower is of 

 the simplest possible description, consisting merely of a naked Ovule. 



Fruit and Seed — 



Fig. 4. Ripe fruit cone, with dry woody scales, opened to allow the escape of the seed. 



Fig. 5. The seed-bearing scale of Pinus has apparently no bract In the ripe cone, owing to the excessive crowding of the parts, 



the bract has become welded to the scale, forming a dense woody mass; whereas in the Larch, the compression of 



the membranous scales is not so great, and the bracts remain distinct. 

 Fig. 6. Detach a seed from the wing, make a vertical section, and examine under low power in glycerine. 



Seed-cover or Testa. 



Endosperm. 



Embryo with several cotyledons arranged spirally. 



Suspensor embedded in endosperm. 



Fig. 7. The ripe Fruit of the Yew has a crimson cup known as the Arillus. It is fleshy and sweet to the taste, and grows 

 from the base of the seed, surrounding it and finally rising above it. The hard-shelled Seed is attached to the bottom 

 of the cup and is poisonous. 



Germination — 



Fig. 8. Germinating Yew with two Cotyledons, which are green. 



Fig. 9. Young plant showing the two green Cotyledons opposite and persistent, and succeeding leaves arranged spirally. 



The leaves of the Yew are seen at first to have a regular spiral arrangement; but as branches are formed, which 

 spread out more or less horizontally, the leaves get twisted upon their stalks and come to lie in one plane, as if 

 arranged in two rows. In that way the original radial symmetry has become bi-lateral. 



CLASSIFICATION. 

 Sub-kingdom. — Phanerogams. 

 Group. — Gy mnosperms. 

 Order. — Coniferae. 



Trees or shrubs, extensively branched. 



Leaves, small, and often needle-shaped. 



Flowers, usually produced in the form of cones. 



Male Flowers, in the form of small cones, or reduced scales bearing pollen-sacs. 



Female Flowers, in the form of cones, or a single Ovule. 



Fruit, woody or scaly cones, or succulent like a berry. 



