MONOCOTVLEDONS. 



619 



manniacege, the parts of the embryo of the ripe seed are not differentiated; it 

 consists of a round mass of tissue on which the plumule is developed only during 

 germination. 



Germma/i'on^ either begins at once with the lengthening of the roots — their 



Fig. 419.— Germination of Phcenix dacfyli/cra : I transverse section 

 of the dormant seed ; III— IV different stages of germination {IV the 

 natural size) ; A transverse section of the se&d at xx in IV; B transverse 

 section at xy, C at jz z; e the horny endosperm, j the slieath of the 

 cotyledon, st its stalk, c its apex developed into an organ of absorption 

 vk'hich gradually consumes the endosperm and at length occupies its 

 place, 7u the primary root, 7v' secondary roots, b' b" the leaves which 

 succeed the cotyledon, b" becomes the first foliage-leaf: in B and C its 

 folded lamina is seen cut across. 



Fig. 420.— Plant QiPolygoiiatum multifloriiin 

 in its second year ; B its stem magnified, iv the 

 unbranched primary root, w' lateral roots spring- 

 ing from the stem st, I foliage-leaf of the second 

 year, k bud, c the scar where the cotyledon was 

 attached, i and 2 scars of the first sheath-leaves 

 which precede the foliage-leaf I. /, // the suc- 

 ceeding sheath or cataphyllary leaves of the bud 

 in B. (C/. Fig. 143) 



protrusion causing in Grasses the rupture of the root-sheath which envelopes them, 

 and which remains attached to the axis of the embryo as the coleorhiza (Fig. 123). 

 — or, as is more commonly the case, the lower part of the cotyledon lengthens, 



See Sachs, Bot. Zeitg. 1862 and 1863. 



