io6 
VISCUM 
Fagus sylvatica , Fraxinus excelsior , Ilex aquifolium , Juglans regia, Platanus occidentalis, P. orientalis, Populus alba , “ P. 
canadensis," P. canescens, P. italica, P. nigra, x P. serotina, P. tacamahacca, P. tremala, Prunus avium , P. domestica , 
P. laurocerasus, P. padus, P. spinosa, Pyrus aucuparia , P. domestica, P. communis, P. malus, P. rnalus var. americana , Quercus 
robur, Rhamnus catharticus, Ribes grossularia, Robinia pseudacacia , Rosa canina, Salix alba, S. caprea, Tilia europaea, Ulmus 
campestris , U. montana, U. montana var. erecta ; Cedrus libani, Taxus baccata, Sequoia sempervirens, Larix decidua. 
Southern Scandinavia, Denmark, Belgium, France, Germany; central Europe (ascending to 
1000 m.), central and southern Russia, southern Europe; northern Africa; Caucasus; Asia Minor 
to Persia and Afghanistan; central Asia to the Amur region and Japan. 
Order 2. tARISTOLOCHIALES 
Aristolochiales Lindley Nixus Plant. 26 (1833); Nat. Syst. ed. 2, 205 (1836); Engler Syll. ed. 1, 100 
(1892); Pflanzenfam., Nachtr. 346 (1897); Ascherson und Graebner Syn. iv, 677 (1912); Asarales Lindley Veg. 
Kingd. 786 (1846) partim. 
For characters, see page 103. Only British family: — Aristolochiaceae. 
Family 1. t ARISTOLOCHIACEAE 
Aristolochiaceae Lindley Nat. Syst. ed. 2, 205 (1836); Solereder in Pflanzenfam. iii, pt. i, 264 
(1894); Ascherson und Graebner Syn. iv, 677 (1912); Asaraceae Link Enum. ii, I (1822) nomen. 
Lianes or perennial herbs. Leaves alternate, long-petioled, exstipulate, simple. Laminae usually 
cordate or reniform, usually entire, rarely lobed. Flowers monoclinous, entomophilous or auto- 
philous, protogynous, honeyless, epigynous or hemi-epigynous. Perianth with usually 3 segments, 
petaloid, actinomorphic or zygomorphic, more or less persistent and adnate to the ovary. Stamens 
6 — 36, usually 6 — 12, either free or more or less adherent to the style. Anthers adnate, extrorse. 
Ovary of 4 — 6, usually 6 carpels, with as many loculi and stigmas. Ovules 00 to each loculus, 
anatropous, horizontal, or pendulous. Placentation axile. Raphe large. Embryo small. Endosperm 
present. Fruit a capsule. Seeds with 2 integuments. 
5 genera ; 200 species ; tropical and warm temperate zones, except Australia. 
British tribes of Aristolochiaceae 
Tribe 1. tAsareae (see below). Aerial stems short. Laminae reniform. Flowers actinomorphic. 
Stamens 12. 
Tribe 2. *Aristolochieae (p. 107). Aerial stems erect, 3 — 6 dm. high, leafy. Laminae 
cordate. Flowers zygomorphic. Stamens 6. 
Tribe 1. \ ASA RE A E 
Asareae Spach Hist. Nat. Vlg. Phan, x, 560 (1841); Solereder in Pflanzenfam. iii, pt. i, 271 (1894); 
Ascherson und Graebner Syn. iv, 678 (1912). 
For characters, see above. Only British genus : — t Asarum. 
Genus 1. t Asarum 
Asarum [Tournefort Inst. 501, t. 286 (1719)] L. Sp. PI. 442 (1753) et Gen. PI. ed. 5, 201 (1754); 
Solereder in Engler und Prantl Pflanzenfam. iii, pt. i, 271 (1894); Ascherson und Graebner Syn. iv, 678 (1912). 
Geophilous, perennial herbs. Rhizome creeping, pungent. Inflorescence solitary. Flowers 
pedicelled. Perianth actinomorphic, with 3 segments, sometimes with 3 additional alternating 
segments. Stamens 1 2 ; connectives usually continued beyond the anthers. Ovary with 6 carpels. 
Capsule subglobular, with irregular or loculicidal dehiscence. Seeds large. 
1 3 species ; north temperate zone. 
