CISTINE.E 189 



Those coming under my notice are spirally coiled much in the 

 same way as in Cistus, but the cotyledons are usually broader 

 and lie in the broader plane of the seed when that is flattened 

 in any way. There are a few slight modifications. They 

 are incumbent as usual, but the radicle in H. Spachii and 

 H. violaceum is displaced at its upper end and lies obliquely 

 over the edges of the cotyledons. This is carried further in H. 

 polifolium, and the broadly oval cotyledons are almost strictly 

 accumbent, lying in the broader plane of the seed with their 

 edges to the hilum. The radicle, as in all the other species 

 examined, is longer than the cotyledons, in some instances 

 about twice as long. 



Cotyledons. There are two leading types of cotyledons 

 represented by the two leading genera, Cistus and Helianthe- 

 mum ; in the former they are comparatively narrow, in the 

 latter broad. Taking Cistus laurifolius (fig. 186) as an illus- 

 tration, the cotyledons are linear-lanceolate, obtuse or subacute, 

 entire, flat or convex above, and subrevolute at the margins, 

 dotted with minute scales on both surfaces, otherwise glabrous, 

 deep green, opaque, with an indistinct midrib, narrowed at the 

 base or shortly petiolate, and connate forming a little cup 

 surrounding the plumule. The seed-leaves of C. undulatus, 

 C. ladaniferus, and C. albidus agree closely in all the leading 

 characters with the above, except that in C. undulatus they 

 are less distinctly petiolate. It may also be noted that the 

 hypocotyl of the latter is finely pubescent, as are both the 

 hypocotyl and petioles of the cotyledons in C. albidus. 



The broad type of cotyledons may be represented by Helian- 

 themum vulgare or H. apenninum (fig. 187). They are broadly 

 oblong or obovate in the latter, distinctly petiolate, entire, tri- 

 nerved in the basal half, but indistinctly so upwards, with the 

 lateral nerves running parallel to the margin, deep green, and 

 glabrous with the exception of the petioles, which are thinly 

 hairy. The hypocotyl is also pubescent. The cotyledons of 

 H. vulgare are broadly oval or subobovate, and one-nerved, but 

 otherwise correspond closely to those of H. apenninum. The 

 lateral veins probably exist, although indiscernible owing to the 

 opaque character of the cotyledons. These are oval-oblong, 

 very large and one-nerved, with hairy petioles shortly connate 



