To book accommodation for the duration of the meeting (Thursday June 12 to Sunday June 15) you can use the following link for special rates at hotels near to the Botanic Garden.

http://www.zuerich.com/en/kongresslandingpages/kongress13.html

To book alternative hotels, or for stays longer than the meeting duration, you can book by contacting Zürich Tourism (by postal mail, phone, email or fax). When contacting Zürich Tourism please ensure you mention that you belong to the "Evolutionary Plant Radiations" group, to take advantage of special rates:
Phone: 0041 44 215 40 40
Fax: 0041 44 215 40 44
E-Mail: hotel@zuerich.com
Website: http://www.zuerich.com/en/Visitor.html

ZÜRICH TOURISM
Hotelreservation
Im Hauptbahnhof
Postfach CH-8021
Zürich

If you prefer to check individual hotels, bellow is a list of the hotels in the vicinity of the conference site and their price ranges (CHF).

		Single room	Double room	3-beds room
	Seefeld (near conference site)
1	Europe	227	323
2	Lady’s First	230	290
3	Seehof	220	253
4	Opera	225	315
5	Ambassador	220	320
	City centre
6	Splendid	80	105	132
7	City Backpacker	77	118	159
9	Astor	155	185
10	Comfort Inn Royal	125	200
12	St.-Josef	140	190	255
14	California	170	190	210
15	Arlette	125	165
16	Basilea	13	160
17	du Théâtre	155	200
18	Zürich Marriott	280	290
19	Adler	155	195
20	Alexander	140	180
21	Franziskaner	210	280
22	Altstadt	210	280
23	Central Plaza	193	233
24	Scheuble	148	198

A numbered map can be found here

More hotels and their websites can be found at:
http://www.accommodation-source.com/hotels/ZRH_zurich/hotels.html
http://www.tripadvisor.com/