PLATE IV.— ANNUAL MEADOW GRASS (Poa annua) and SAND CAREX (Carex arenaria). 



Grass. 



The Grass chosen is common everywhere by the road-side, and may be had in flower at almost any season of the year. The 

 flower is exceedingly small, and when the season permits the flower of Wheat might be examined instead. 



Grasses are usually wind-fertilised— the pollen is wafted from flower to flower, and thus there is an interchange of pollea In > acc°ra- 

 ance with this arrangement, the flower is inconspicuous and without gaudy colours, the anthers hang out on long filaments and turn aoout 

 with every breath of wind, and the stigma is a branching tree, in miniature, to entangle the pollen as it passes. 



Some, however, are self-fertilised — and the Annual Meadow Grass is an example. 



Fig. 1. General characters. 



Root, fibrous. . . _« , _ A fVlof ^y.^ 



Stem, hollow and jointed. In the quickly growing stem, the outer parts grow faster than the inner, so that : tnc 



interior is ruptured and a hollow produced. The fibro-vascular bundles form a horizontal partition at the nodes, 



and thus strengthen the stem. 

 Leaves, linear and alternate, with pointed membranous Ligule at junction of sheath and blade 

 Inflorescence consisting of an axis with branches bearing stalked flowers. 

 Spikelet composed of several flowers. 



lg. et etac^e^ ^ ^^ ^ the ^ imbricating with each othe r, and the axis of the spikelet bears the flowers. 



Fig. 3. Floret detached. . , . . «_„ 



The Stigma in the centre is seen to be branched and hairy in order to intercept and retain the pollen. 

 The Anthers are placed on slender filaments. 



The Flowering glume and Pale are simply bracts overlapping each other. 

 Fiff 4. Under the dissecting microscope detach the different parts of the flower, by steadying it with needle in left hand and 

 removing parts with cutting needle in right Remove the flowering glume and two little scales will be seen side by 

 side, embracing ovary opposite to pale, and one stamen coming out between them. Great care and steadiness of hand 

 is required in removing these entire, so that they may be laid out and examined. t 



The Flower is extremely simple, consisting of two little scales, three Stamens, and two Carpels, as indicated by 

 the two Stigmas — 



Little scales or Lodicules probably representing a Perianth. 



Stamens three, alternating with lodicules. The anthers hang down because the fi.aments are weak. 

 Carpels consisting of swollen Ovary, crowned by two diverging feathery Stigmas. 

 Diagram I.— Plan of flower, showing the parts at one level and in their proper relations. 

 Perianth of two free segments. 

 Andrcecium of three Stamens. 

 Gyncecium of two united Carpels. 

 Diagram II.-By comparing a number of flowers it is possible to construct a theoretical diagram, showing the flower of which 

 grass may be a reduced form. In the Rice flower, for instance, there are two rows of stamens of three each. 

 This diagram will be seen to agree with that cf the Lily in the following Plate. 

 Fig. 5. Ovary with spreading Stigmas. 

 Figs. 6 and 7. Grains of Wheat soaked in water and sections made. 



Embryo is at base of seed, and the rest filled up with mealy Endosperm. 

 Fig. 8. Place a few grains of wheat in flannel, keep moist and at a moderate temperature, and germination will soon begin. 

 Fig. 9. Root-hairs^ ^ ^ ^ ^ ^ ^ drawn QUt intQ delicate root . hairs . These root-hairs being so 



thin are extremely permeable to fluids, and it is through them the root withdraws from the soil the necessary plant- 

 food. 



Sedge {from Luerssen). 



Sed-es may be contrasted in their general structure with Grasses. The Stem is solid and usually triangular The Leaves are arranged 

 in three 3 row?on the stem and the sheath is not split. The Flowers are developed in .cale-like bracts called glumes, as in grasses, 

 but are usually male and female, and not bi-sexual like the flower of Grass. 

 Sedges are mostly found in damp places. 

 Fig. 10. Triangular Stem. 



Fig. 11. Spike bearing Female spikelets at bottom, female and male spikelets about middle, and entirely Male spikelets at top. 

 Fig 12 and Diagram III.— Male Flower consisting simply of three Stamens enclosed by a bract 

 Fig. 13*. and Diagram IV.— Female Flower consisting of two united Carpels, and the bracteole has grown completely round, 



enclosing it as in a bottle. 

 Fig 14. Fruit is of a chestnut colour, and invested by the enlarged bracteole. 



Diagram V.-In Carex the flower is seen to be really borne on an aborted axis, which arises in the axil of the outer bract. 

 In Elyna this ax.s is seen to develop further, producing not only a Female but also a Male Flower. 

 The apparently single flower in the case of Carex would thus seem to be a reduced Inflorescence. 



CLASSIFICATION. 



Group — Angiosperms. 



Ovules enclosed in an Ovary. % t , 



Endosperm, not formed in Embryo-sac before fertilisation. 

 Class. — Monocotyledon. 



Leaves with parallel veins. 



Parts of Flower in threes. 



Embryo with one Seed-leaf or Cotyledon. 



