436 FOURTH GROUP.— SEED-I LANTS. 



in some species of Aloe, Carcx and Pandanus ; spiral arrangements with smaller 

 divergences than \ are sometimes found, as in Musa ; in Musa rubra acQordmg to 

 Braun the foliage-leaves have a divergence of f, the bracts of jy ; in Coslus the 

 angle ol divergence of the foliage-leaves is \ or 4, etc. The axillary shoot of the 



Fig. 361. Croc 



!s. .-! the 

 ; of irisertion of tlie scale-leaves yX/ are seen forii 

 to these leaves ; d the base of the dead leafy and flowering sten 

 ew tuber and a new flowering stem are formed. D longitudinal 



/ foliage-leaves, /; bract, / peri: 



rtth, 



anthe 



i; i a bud in the axil of a foliagcleaf. 



, B from beneath, C from the side in longitudinal 

 ig closed circles, and the axillary buds H belong- 

 and by its side J!i in C the new bud, from which 

 iction through the Hew bud ; «« its scale-leaves. 



Monocotyledons usually begins with a leaflet which is generally two-keeled and has 

 its dorsal surface closely applied to the primary axis ; such a leaf for instance is the 

 upper palea in the flower of the Gramineae, which is itself a shoot axillary to the 

 lower palea ; where the leaves of the successive generations of shoots alternate in two 

 rows it follows that an entire system of shoots may 

 be bilateral, and divisible by a plane which divides 

 the leaves into halves, as in Po/amoge,'on and Typha. 

 The inSertioil of the scale-leaves and foliage-leaves, 

 and ofl:en also of the bracts (for instance of the 

 spathe which is so common), is usually either wholly 

 or to a great extent amplexicaul, and the lower part 

 of the leaf is consequently sheathing ; there is an 

 obvious connection between this and the absence of 

 the stipules which are so common in Dicotyledons. 

 The scale^eaves, rudimentary arrested states of 

 foliage-leaVes, and many bracts are reduced to this 

 sheathing portion, which in the foliage-leaves usually 

 passes immediately into the green lamina, though a 

 comparatively long and slender stalk occurs between 

 the lamina and the sheath in the Scitamineae, 

 Aroideae, Palmae and some other forms. If there is no stalk and the lamina and 

 sheath are sharply distinguished, there is often a ligule present at the point where 

 they meet, as in the Gramineae and Allium ( Fig. 363). 



The lamina is usually entire and of very simple outlfne, often long and narrow 

 (ribbon- shaped), seldom roundish and discoid {Hydrocharis), or cordate or sagittate 

 {Sagiltaria and some Aroideae) ; branching of the lamina is of rather rare occur- 

 rence, and appears either in the form of lobes united by a broad base, or les 



FIG. 31=2. Atlium L,pa. 

 bulb after removal of the b 

 broad short portion of stem i 

 scales are inserted A shows 

 the sheaths of the foIiage-lea\ 

 still short. In B the outer 1( 

 moved, and an axillary bud k 

 the side of the terminal bud k 



ales; st the 

 ch the bulb- 

 ninaat /and 



