THE LEAVES. 



25 



hastate (/. hastata), vrhen tlie two lobes are nearly perpendicular to the petiole, 

 like a halbert {Sheep's sorrel, fig. 89) ; — peltate (/. 

 peltatum), when the petiole is joined to the centre of 

 the under surface of the blade {Nasturtium., fig. 90), 

 in which case the primary nerves diverge symmetri- 

 cally from the petiole, like the spokes of a wheel. 

 A peltate leaf may be compared with the orbicular 

 palmately-nerved leaves of Mallows, for if the two 



90. Naaturtiuni. Peltate leaves. 



91, Curled Mallow. 



edges nearest the petiole of the leaf of the small Mallow (fig. 74) were joined, a 

 peltate leaf would be the result. 



Surface of Leaves. — Leaves are smooth {/. Iwvia), when their surface presents 

 neither hairs nor inequalities {Orange); — scabrid {f.scabra), when rough or harsh to 

 the touch {Carex); — glabrous {/. glabra), when, whether smooth or not, they have no 

 hairs {Tulip) ; — silJcy {f.sericea), when clothed with long, even, shining hairs {Silver- 

 weed) ; — -pubescent or downy (/. pubescentia), when they are clothed with soft short 

 hairs {Strawberry) ; — pilose {/. pilosa), when the hairs are long and scattered {Herb- 

 Robert) ; — villous {/. villosa), when the hairs are rather long, soft^ white, and 

 close {Forget-me-not) ; — hirsute (/. hirsuta), when the hairs are long and numerous 

 {Rose-campion) ; — hispid (/. hispida), when they are erect and stiff {Borage) ; — setose 

 (/. setosa), when they are long, spreading, and bristly {Poppy) ; — tomentose (/. tomsn- 

 tosa), when they are rather short, soft, and matted {Quince) ; — woolly (/. lanata), 

 when lorig, appressed, curly, but not matted {Corn- centaury) ; — velvety (/. velutina, 

 holosericea), when the pubescence is short and soft to the touch {Foxglove) ; — cobwebby 

 (/. arachnoidea), when the hairs are long, very fine, and interlaced like a cobweb 

 {Thistle, Gobivebby Houseleeh). 



Leaves are wrinkled or rugose {/. rugosa), when their surfa-ce presents in- 

 equalities, due to there being more parenchyma than is enough to fill the spaces 

 between the nerves {Sage) ; — bullate (/. bullata), when this "Excess of parenchyma 

 renders the inequalities more visible, and the whole blade is swollen between the 

 nerves {Cabbage) ; — crisped (/. crispa), when the extra parenchyma only appears at 

 the edge of the blade, which appears crimped {Curled Mallow, fig. 91) ; — waved 

 (/. undulata), when for the same reason the edges are in rounded folds {Tulip). 



