PHANEROGAMIA 645 



adhere, together with the seeds, to branches against which the birds rub 

 their beaks. The root on germination forms an expanded, attaching disc. From 

 the centre of this a sucker, which has no root-cap, penetrates the rind of the 

 branch as far as the wood. From the base of this lateral roots arise, which grow 

 in the rind giving off secondary suckers. As the wood of the host grows in 

 thickness year by year, the tips of the suckers become embedded in the new 

 wood. Their tips become converted into permanent tissue, while further growth 

 in length is effected by a zone corresponding in position to the cambium of the 

 host plant. 



Family 4. Rafflesiaceae ( M ). Family 5. Balanophoraceae ( 4U ). The plants be- 

 longing to these families are almost all tropical. They are parasitic, without chloro- 

 phyll, and with their vegetative organs 1'educed to haustoria. They have sometimes 

 very large flowers (Rafflesia] or large inflorescences bearing numerous small flowers. 



Rajflesia Arnoldi (Sumatra) has the largest of all known flowers, which attain a 

 diameter of 1 metre. Many species of Balanophora are apogamous. 



Series II. Sympetalae ( 15 ) 



Perianth differentiated into calyx and corolla. Corolla gamo- 

 petalous. Flowers usually pentamerous, always cyclic. Two groups 

 of Sympetalae can be distinguished. A. Pentacydicae. Flowers 

 with five regularly alternating whorls. K5, C(5), A 5 + 5, G(5). 

 B. Tetracydicae. Flowers, by omission of the inner whorl of 

 stamens, no trace of which persists, composed of four regularly alter- 

 nating whorls. Ko, C(5), A 5, G(5) or more commonly G(2) by 

 reduction in the number of carpels. 



A. PENTACYCLICAE 

 Order \. Erieinae( 41 ) 



Plants with actinomorphic flowers; androecium obdiplostemonous ; 

 stamens not adherent to the corolla. Pollen-sacs with an " exothe- 

 cium " ; pollen-grains frequently cohering in tetrads. Ovary, as a 

 rule superior, multilocular. 



Family 1. Ericaceae. Evergreen, shrubby 

 plants with small, often needle-shaped leaves. 

 Anthers opening by pores or splits, frequently 

 provided with horn-like appendages, on which 

 account the group is also termed Bicornes. 

 Fruit, a capsule, berry, or drupe. Seeds with 

 a well-developed embryo and abundant endo- 

 sperm (Figs. 709, 710). 



FIG. "Oi>. Kloral (liairiani of 



IMPORTANT SUB-FAMILIES AND GBNKBA. A. With j /;, (Ei-irac-a.-). 

 ,i Miperior ovary : 1. Ericeue. K4, 0(4), A4 + 4, G(4). 



Corolla persistent. Erica, calyx shorter than the corolla, includes some British 

 species (E. Tetrulix) and many native to the Mediterranean region and the 

 Cape. Calluna, calyx longer than the corolla. C. vulgaris, Heather or Ling, 



