THE LEAVES. 



25 



hastate (f. hastata), when the two lobes are nearly perpendicular to the petiole, 

 like a halbert (Sheep's sorrel, fig. 89) ; peltate (f. 

 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. Nasturtium, 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 (f. Icevia), when their surface presents 

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

 the touch (Carex); glabrous (f. glabra), when, whether smooth or not, they have no 

 hairs (Tulip] ; silky (f.sericea), when clothed with long, even, shining hairs (Silver- 

 tveed) ; pubescent or downy (f. pubcscentia) , when they are clothed with soft short 

 hairs (Strawberry} ; pilose (f. pilosa), when the hairs are long and scattered (Herb- 

 Robert] ; villous (f. villosa), when the hairs are rather long, soft, white, and 

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

 (Rose-campion) ; hispid (f. hispida), when they are erect and stiff (Borage] ; setose 

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

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

 when long, appressed, curly, but not matted (Corn- centaur y) ; velvety (f. velutina, 

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

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

 ( Thistle, Cobwebby Houseleejc) . 



Leaves are wrinkled or rugose (f. rugosa), when their surface presents in^ 

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

 between the nerves (Sage) ; bullate (f. bullata), when this excess of parenchyma 

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

 nerves (Cabbage) ; crisped (f. 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). 



