Fig. 23. Very young ovulum of Ruta graveolens: a, the primine; b, the secundine; c, the nucleus. In the end, the primine extends, contracts at its foramen, and closes over the secundine and nucleus. Fig. 24. Vertical section of an ovulum of Alnus glutinosa: a, the umbilical cord; b, foramen; c, primine (and secundine perhaps united with it); d, nucleus; e, vessels of the raphe; ƒ, place of the chalaza. Fig. 25. An oblique vertical section of the fertilised ovulum of Tulipa Gesneriana: a, foramen of the primine (or Exostome); b, foramen of the secundine (or Endostome); c, primine; d, secundine; e, nucleus, its apex concealed within that of the secundine; ƒ, vessels of the raphe; g, place of the chalaza. Fig. 26. Ovulum of Lepidium ruderale; after A. Brongniart: a, umbilical cord; b, foramen; c, point of the nucleus seen through the primine and secundine. Fig. 27. Half-ripe seed of the same, cut through perpendicularly; after Brongniart: a, the umbilical cord; b, foramen; c, primine; d, secundine; e, nucleus; f, embryo partially formed, its radicle pointing to the foramen; g, the point where the nourishing vessels of the placenta expand (the chalaza). Fig. 28. A perpendicular section of the ripe seed of the same; after A. Brongniart. The primine and secundine are consolidated, and the nucleus is entirely absorbed by the embryo. a, Umbilical cord; b, foramen, now become the micropyle; g, chalaza; h, cotyledons of the embryo; i, radicle; k, plumula. Fig. 29. Mode of fertilisation in Cucurbita Pepo; after Adolphe Brongniart: a, a portion of the placenta; b, ovulum; c, its foramen; d, the bundle of stigmatic tissue through which the fertilising matter is conveyed, and to which the foramen is closely applied; e, the bundle of vessels that communicates with the umbilicus; f, the commencement of the raphe. PLATE VI. Fig. 1. A, Vertical section of the seed of Canna lutea: a, albumen; b, embryo. -B, Embryo extracted and divided vertically: a, cotyledon; b, plumula concealed within the embryo; c, radicle, with internal rudiments of roots. Fig. 2. A, Vertical section of the seed of Myrica cerifera: a, cotyledons; b, radicle; c, plumula; d, remains of foramen; e, hilum. - B, Embryo extracted entire: a, cotyledons; b, radicle. Fig. 3. Vertical section of the seed of Luzula campestris: a, albumen; b, embryo. Fig. 4. Vertical section of the grain of Bromus mollis: a, albumen; b, embryo; its plumula; d, its cotyledon; e, its radicle, with internal rudiment of a C, root. Fig. 5. Vertical section of the seed of Rheum rhaponticum: a, albumen; b, embryo; c, hilum; d, remains of foramen. Fig. 6. A, Seed of Triglochin palustre: a, fungous chalaza; b, raphe; c, hilum. - B, Embryo of the same: a, cotyledon; b, radicle; c, fissure, within which the plumula lies. - C, The same halved vertically: a, cotyledon; b, radicle; c, fissure; d, plumula. Fig. 7. A, Seed of a species of Begonia: a, hilum. B, The dicotyledonous embryo. Fig. 8. Coiled up embryo of Basella rubra: a, radicle; b, cotyledons. Fig. 9. Vertical section of the seed of Mesembryanthemum crystallinum: a, albumen; b, radicle of the embryo. Fig. 10. Anatomy of the grain, and germination of Scirpus supinus; after Richard. A, Vertical section: a, albumen; b, embryo.-B, The embryo extracted, enlarged, and halved vertically: a, cotyledon; b, radicle. — C, The seed germinating and halved: a, albumen; b, cotyledon; c, plumula; d, young root; e, sheath of the latter. Fig. 11. A, Seed of Ribes rubrum: a, chalaza; b, raphe; c, hilum. - B, The same, halved vertically, showing the minute embryo, with two spreading cotyledons lying at the base of the albumen: b, section of the raphe; c, hilum; d, albumen. Fig. 12. Embryo of a species of Mammillaria; the cotyledons very small. Fig. 13. Embryo of Geranium Robertianum: a, radicle; b, line of union of the two cotyledons; c, one of the plaits in the latter. Fig. 14. Section of the seed of Alisma Damasonium; after Mirbel: a, cotyledon; b, radicle; c, plumula. Fig. 15. Part of the seed of Olyra latifolia; after Richard: a, albumen; b, back cotyledon; c, front ditto; d, radicle; e, plumula. Fig. 16. Embryo of Ruppia maritima; after Richard: a, plumula; b, cotyledon. Fig. 17. Vertical section of the seed of Pekea tuberculosa; after Richard: a, radicle; b, collet; c, cotyledons. Fig. 18. Embryo and ruminated albumen of Eupomatia laurina (a vertical section); after Ferdinand Bauer. Fig. 19. Spiral twisted embryo of Cuscuta europæa. Fig. 20. Half the embryo of a bean (Vicia Faba); after Mirbel: a, one of the cotyledons; b, plumula; c, radicle; d, scar from which the other cotyledon has been cut. Fig. 21. Germination of Lachenalia serotina: a, albumen; b, cotyledon; c, plumula; d, radicle. Fig. 22. Germination of Calla æthiopica; after Mirbel: a, exterior elongation of the cotyledon; b, seed; c, front leaf of the plumula; d, radicle. Fig. 23. Germination of Allium Cepa: a, albumen; b, embryo elongated beyond the testa. Fig. 24. The same further advanced: a, seed; b, base of the cotyledons; c, radicle or young root; d, plumula. Fig. 25. Germination of Baptisia australis; after De Candolle: a a, cotyledons. Fig. 26. Germination of Cercis Siliquastrum; after De Candolle; a a, cotyledons. Fig. 27. Theca, or Sporangiola, of Erysiphe adunca; after Greville. Fig. 28. Sporules of Phascum crassinervium; after Greville. Fig. 29. Asci, or Theca, of Sphæria tubæformis; after Greville. Fig. 30. Theca of various Lichens; after Von Martius. |