178 



FLORAL ENVELOPES. COROLLA. 



373. According as the veins proceed in a straight or curved direc- 

 tion, so may the limb of the petal be flat or concave, or hollowed like 

 a boat, cymbiform or navicular (cyrnba, a boat, and navis, a ship), or 

 like a spoon, cochleariform (cochleare, a spoon). In the case of the 

 navicular petal, the median vein forms a marked keel. In Hellebore, 

 the petals become folded in a tubular form, resembling a horn ; in 



Aconite (fig. 284), some of the 

 petals, p, resemble a hollow 

 curved horn, supported on a 

 grooved stalk, while in Colum- 

 bine (fig. 285), Violet, Snap- 

 dragon, and Centranthus, one 

 or all of them are prolonged 

 in the form of a spur, and are 

 calcarate (calcar, a spur). In 

 Valeriana, Antirrhinum, and 

 Corydalis, the spur is very 

 short, and the corolla or petal 

 is said to be gibbous (gibbus, a 

 bunch or swelling), or saccate 

 at the base. In some Bora- 

 ginacea? (fig. 297), there are 

 foldings at the upper part of 

 the tube of the corolla, r, caus- 

 ing hollow projections, open 

 on the outside, which might be considered as small internal spurs. 



374. When a petal continues narrow, as if formed by a prolonga- 

 tion of the claw, it is called linear; when the limb is prolonged below, 

 so as to form two rounded lobes, it is cordate, as in the petal of Genista 

 candicans (fig. 286), and when the lobes are acute, it may be sagittate 

 or hastate. The meaning of the epithets applied to the forms of petals, 

 will be understood by considering those applied to leaves. In general, 

 it may be stated, that the terms refer to the limb of the petal, which is 

 frequently the only portion developed. In the Poppy, the petals have 

 a puckered or corrugated appearance, arising from their delicacy, and 

 the mode in which they are folded in aestivation. Other petals have 

 a crisp or wavy margin. 



375. A corolla rarely consists of one petal, and when this occurs, 

 as in Amorpha, it depends on the abortion or non-development of 

 others. Such a corolla is unipetalous (unus, one), a term quite distinct 



Fig. 284. Part of the flower of Aconitum Napellus, showing two irregular horn-like petals, p, 

 supported on grooved stalks, o. These used to be called nectaries, s, The whorl of stamens 

 inserted on the thalamus, and surrounding the pistil. 



Fig. 285. Single spurred petal of Aquilegia vulgaris, or common Columbine, formed by a 

 folding of the margins. 



Kg. 2S:>. Cordate or cordiform petal of Genista candicans. o, The claw. I, The limb. 



