103 
The Evansia Section 
The following specimens are probably from cultivated plants : 
Pekin, 1889, Bodinier (L). 
Ootacamund, 1856, Cleghorn (E). 
Yokohama, 1862, Maxim. (K). 
Shanghai, 1 861-61, Maingay, no. 742 (K), 
Diagnosis. 
/. tectorum Evansia ; /. Milesii haud dissimilis sed rhizoma pallide fuscum nec viride ; caulis foliis 
subaequalis. 
Description. 
Rootstock, a stout, pale, buff-coloured rhizome with sessile shoots, not producing stolons, as do 
most of the other members of the Evansia section. 
Leaves, thin, pale green, ribbed, 12 — 18 in. long by 1 — 2 in. broad, tapering to a point. 
Stem , about 12 in. or rather more in a well-grown plant, bearing reduced leaves and one or two 
lateral heads. 
Spathe, 2 — 3 flowered, valves green, pointed, 1^ — 2 in. long. 
Pedicel, about ^ in., but becoming eventually somewhat longer. 
Ovary, rounded, trigonal, green. 
Tube, 1 — 1£ in., brown purple. 
Falls, blade almost orbicular, marked with deep lilac veins and mottlings on a paler ground ; crest 
white, marked with brown violet, deeply and irregularly laciniated ; haft about half as long as the 
blade, with red lilac veins on a white ground, and wavy edges. 
Standards, blade lilac, obovate, suddenly contracting to a short haft, of which the edges curl over 
to form a tube. The standards are spreading and slightly concave on the upper surface. 
Styles, narrow, over an inch long. 
Crests, quadrate, finely serrated. 
Stigma, prominent, bilobed, blue. 
Filaments, about equal in length to the anthers, colourless. 
Anthers , cream coloured. 
Pollen, white. 
Capsule, oblong, rounded with 6 ribs, walls of thin tough texture, with a coarsely netted surface, 
rather more than i£ in. long. 
Seeds, numerous, globose or pyriform, dark black brown, with small but distinct cream-coloured 
aril. 
Observations. 
This fine Iris was first introduced into Europe by Siebold, who sent plants to St Petersburg, and 
it was one of these plants that provided the material for Regel's figure (Gartenflora t. 716). According 
to Bretschneider (Bot. Sin. iii. 154), the cultivation of this Iris in China can be traced back to the 
seventh century and it is now widely distributed over the country. The Chinese name for it is 
apparently Yuan wei, while in Japanese the same character is read Itsi hatsu (fide Dr Takeda). 
Kaempfer in his Amoenitates exoticae (1712), p. 873, mentions it under the name of "itz fatz." 
The name is derived from the fact that in Japan this Iris is largely grown on the ridges of 
thatched roofs, in the same way that I. germanica and other Pogoniris are commonly grown in 
Normandy at the present day. Clay is probably used to fix the plants in position. 
In England the cultivation of this Iris is not really difficult, provided only that the rhizomes are 
thoroughly ripened in late summer, and that thorough drainage is provided at all times. When these 
conditions are not fulfilled, the plants are apt either to die entirely or more usually to lapse into 
a dormant condition and produce no flowering growths in the following season. For instance, the wet 
and sunless summer of 1910 so weakened my plants that flowers were scarce in 1911, but the effect 
of the hot summer of 1911 was very obviously shown by the sturdy growths made in that year. 
Of late years an albino variety has appeared in cultivation, though whether it arose from seed 
in Europe or was introduced from the Far East is uncertain. /. tectorum alba has pure white flowers 
except for a few faint yellow veins at the base of the segments and on the white crest. The absence 
of blue pigment in this Iris acts as a Mendelian recessive character and consequently the seedlings 
raised from self-fertilised seed are all white flowered. I have raised more than a hundred seedlings 
of tectorum alba and found no variations. One curious fact has been that, although the blue type 
always has a branching stem, no albino plant has ever in my garden borne more than two flowers on 
an unbranched stem. However, this proved not to be a fixed character, for the same plants, when 
grown in the more genial climate of the Channel Islands, produced stems with lateral branches. 
I. tectorum grows rapidly and seems quickly to exhaust the soil in which it grows. The plants 
should therefore be transplanted every two or three years and the operation will result in no loss of 
bloom if it is carried out in July or early August. Each new growth will form a flowering plant by 
the following year. The exact composition of the soil seems to be of no great moment. 
