338 



NATURAL HISTORY OF PLAXTS. 



orif^nally resembled the former. The fruit (figs. 377, 378) is 

 multiple, formed of a variable number of achenes, enveloped in a 

 common sac or indusium, which represents the lloral receptacle, now 

 become fleshy throughout,' surmounted by the withered sepals or 



their cicatrices. Each achene is 



Rosa cnnina (Dim Hosp). . . , n •, i» • 



glabrous, or part ot its surface is 

 hairy." Its walls are very hard 

 and thick,' and surround a de- 

 scending seed with membranous 

 coats, containing a fleshy embryo 

 with a superior radicle and elon- 

 gated cotyledons, touching by 

 their flat surfaces. There is no 

 albumen. 



The Eoses are shrubs, ere(;t, 

 branching, or creeping and climb- 

 ing. Most of them are covered with prickles of suberous nature,' 

 scattered over the stems, the petioles, the veins of the leaves, and the 

 peduncles. Others are glabrous ; others, again, are covered \viih 

 glandular hairs. The leaves are alternate, imparipinnate, with the 

 leaflets often serrate ; and are provided with two broad membranous 

 stipules, adnate to the petiole for a great part of their extent, and 

 forming an incomplete sheath. In 7?. herhenfoJia,'' of which it has been 

 proposed to make a distinct genus under the name of Jlidtemia," the 

 leaves are reduced to a single leaflet, or perhaps rather to the base 

 of the petiole, on each side of which the stipules are much developed. 



Fig. 378. 

 jong. section of fruit. 



' The transformation into fleshy tissue may 

 even extend to tlic peduncuhir portion of tlic 

 floral axis ; in certiiin forms of R. alphin, for 

 instance, tlie sinnmit of tlu! pechnule is red and 

 ■uccuk-nt, like tlie iiuhisiuin. The outer sur- 

 face of the hitter often hears the hairs or priekles 

 whicli nlrtady existed in the flower, and may 

 now liave increased in size. In the intervals 

 between the aehenes, too, the inner Knrfaco 

 bears the hi.im whi.h we h:ive already described 

 on the disk (sei' p. ;j:j7, note 2). 



' Kt.i.e<ially on the two cdgen, more or less 

 projec-tiMf? townnis the centre, and the walls )f 

 the receptacle, like those seen in Ctilt/iunthus. 

 Should one alone of these edges have hairs, it is 

 usually the one on the opi)oiiito tide to the inser- 

 tion of the style. 



* The nuwocarp, which is quite dried up when 



ripe, is in some species fleshy and pretty thick 

 during nearly all the i)criv)d of nuituration. The 

 fruit is then rather a drupe ; wo have made the 

 same observation as regards Calyi'anthr<e. 



* They are formed hy a hyiKTtrophy of the 

 corky liiyer, here forming a large nuuilH>r of 

 projictions with lenticular bases, the growth of 

 which ])roduces no rupture in the epidermis, so 

 that this rises up over the whole of the prickle 

 to cover it with a thin layer. 



» Tam.., .Vor. Act. Pitrop., x. 379, t. 10, flg. 

 5. — DC, J'roilr., u. 25.— Kku. & TiioK., Jio*., 

 i. 27. — R. simplicifolia Saiisii.. I/ort. Altrrt., 

 ar.i) (ex LiNDL., Ros., 1) ; J'ar. /,<.»</. t. UH. 



" IJUMoliT., Ao/f itiir /■llidthemia. — Knm.., 

 Oen., n. (5358. — Lowia I.I.ndi,., Bot. Rri;., t. 

 12r)l.— Spach, S^i/. A RtiJfhH. ii. XT.— Rho. 

 (liipuLi liKDKn., Fl. Alt., ii. 221 (nee Kmu.). 



