266 THE JOUBXAL OF BOTANY 



Gr. A. Auden, prepared for the meeting of the British Association, 

 1913, 46(3, says, in speaking of the Algie of the Midlands (meaning 

 the Birmingham district — which onl}^ overlaps the county of Leicester 

 to a small extent), that they are uncommon. The only forms found 

 in the reproductive state are: — M. gennflexa (Dillw.) Ag., Burley 

 Pond (Rutland), August 3/15; Ditch, Narborough, November 4/15, 

 M. scalar is Hass., Woodle Head (Rutland), May 29/15, and 

 31. viridis (Kiitz.) Wittr., High Sharpley, May 9/15, Blackbrook 

 Reservoir, May 25/15, and Timberwood Hill, June 2/14. 



Probablj' the commonest species of Zi/gnema is Z. eruciatum 

 (Vauch.) Ag., but as zygospores have never once been found in the 

 recent collections, identification is not to be relied upon. Amongst 

 Bates's slides zygospores may be seen in Z. Vauclierii Ag. (Charn- 

 wood Heath, May 22/84), and in Z. eruciatum (Canal, near Blaby, 

 July 30/83). Conjugation has been observed occurrmg at Sawley 

 Bridge (May 24/13), and Saddington Reservoir (May 22/15). 



8piroc/yra is not only one of the commonest alga; met with, but 

 it is also found fruiting very freely, and as many as twenty species 

 have been identified. It has been found in every month of the year 

 except October and December. The close of the summer phase 

 observed by Fritsch and Rich (Ann. Bot. xxi. 423-436) and conKrmed 

 by them (Ann. Biol, lacustr. vi., 1913) and Delf (New PhytoL, 

 Feb., Mar., 1915) is well marked. The autumnal phase is, as 

 has been observed, a short one, and there is a gap between 

 this and the vernal phase. S})irogyra becomes common quite 

 earh* in the year, appearances having been recorded for Jan. 3/15, 

 Jan. 6/16 ("two ponds), Jan. 16/16, Jan. 20/16 (2 ponds), and 

 Jan. 30/16 (two pieces of water). Reproduction is observed to take 

 place sexually most commonly in May, but this process begins 

 irregularly in April and goes on to July. Conjugation does occur, 

 however, in March, and zygospores have even been observed as early 

 as February (Sileby 1913, VVhissendine in Rutland 1916 — but see 

 infra'). Tliere is one record only for the presence of zygospores as 

 late in the _year as September, and that is in the case of aS'. nitida 

 (Dillw.) Link (Gallows' Lane, Willesley, Sept. 4th, 1915). On the 

 whole, the Leicestershire Spirogyras bear out the observations pre- 

 viously (Prelim. Observations on Spiroc/i/ra, loc. cit.) recorded — that 

 sexual reproduction in this genus occurs almost exclusively in the 

 vernal phase. The occun-ence of quantities- of S. nitida in the 

 reproductive stage in September 1915 is worth noticing, for it is 

 a form that nearly always reproduces in the early summer : — May /15 

 at Croft, at Swithland, and Ratclifte on the Wreake ; May /05 in 

 Abbot's Pool, Bristol; June /02 at Kew. S. varians (Hass.) Kiitz. 

 keeps constantly to April and May for the formation of its z3'go- 

 spores ; April /13 Lea Lane, April /15 Narborough, April /16 

 Atherstone, May /15 Measham, May /15 Woodle Head, no other 

 dates whatever being recorded. S. affinis, which was previously 

 found (Ann. Bot. xxi. 433) to have rather a long reproductive period, 

 extending from April to July in Abbot's Pool, and from September 

 to November in Telscombe Pond, was only found with zygospores late 

 in May; Swithland, May 31/13, Woodle Head, May "29/1 5, Croft, 



