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Ten-year-old 'Tai So' lychee (Litchi chinensis Sonn.) trees growing on a sandy loam soil in subtropical South Africa (latitude 25 degrees S) were watered weekly (well-watered treatment) or droughted from late July until January (drought treatment). After 16 weeks, at which time the trees obtained most of their water from below 150 cm, average soil water content at 0 to 150 cm depth was 14.5 +/- 0.1% in the well-watered treatment and reached a minimum of 7.6% in the drought treatment. At Week 7, minimum leaf water potential (Psi(L)) in the morning and early afternoon declined to -2.6 and -2.8 MPa, respectively, in droughted trees compared with -1.5 and -2.2 MPa, respectively, in well-watered trees. From Week 9, stomatal conductance and net CO(2) assimilation rate ranged from 70 to 300 mmol m(-2) s(-1) and 3 to 13 micro mol CO(2) m(-2) s(-1), respectively, in well-watered trees. The corresponding values for droughted trees were 50 to 180 mmol m(-2) s(-1) and 2 to 6 micro mol CO(2) m(-2) s(-1). Five weeks after rewatering the droughted trees, gas exchange had not recovered to the rate in well-watered trees, although tree water status recovered within a week of rewatering. In the well-watered trees, water use (E(t)) was 26 +/- 1 mm week(-1) with evaporation (E(p)) of 20 to 70 mm week(-1) indicating a crop factor (k(c) = E(t)/E(p)) of 0.4 to 1.2. Before anthesis, tree water status did not affect extension growth of floral panicles or leafy shoots. In contrast, no vegetative shoots were initiated after fruit set in the droughted trees when Psi(L) in the morning declined to -2.5 MPa. Water deficits reduced initial fruit set by 30% and final fruit set by 70% as a result of fruit splitting (41.2 +/- 4.0% versus 10.0 +/- 1.3%). Water deficits did not alter the sigmoidal pattern of fruit growth, but reduced yield from 51.4 +/- 5.5 kg tree(-1) in well-watered trees to 7.4 +/- 3.3 kg tree(-1) in droughted trees.

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A new Albogiossiphonia species from Egypt is described and figured. This leech is placed in the genus Alboglossiphonia on the basis of having three pairs of eyes, diffuse salivary glands, seven pairs of crop caeca, and the attachment of its eggs to the venter. It differs from other Alboglossiphonia species with seven pairs of crop caeca in its combination of very prominent dorsal papillae, two annuli between the gonopores, lobed first six pairs of crop caeca, and paired ducts of male system at peak of activity with conspicuously differentiated sperm duct, seminal vesicle and ejaculatory duct regions.

A study of well over one thousand specimens provided proof to put the conspecifity of the two supposed species originally described as Helobdella tricarinata and Clepsine nilotica beyond all doubt. Evidence is presented which indicates that the striking changes in body-shape and drastic alteration in the appearance of the tuberculation at different stages of reproduction and nutrition combined with individual variation in tuberculation, annulation, and in the arrangement and pigmentation of the eyes were responsible for earlier confusion as to the identity of this species. Since the early accounts were incomplete and contained some important errors Batracobdelloides tricarinata is redescribed and, for the first time, comprehensively figured.