JOURNAL OF THE ROYAL SOCIETY OF WESTERN AUSTRALIA VOLUME 53 PART 2 1970 REGISTERED AT THE G.P.O., PERTH FOR TRANSMISSION BY POST AS A PERIODICAL THE ROYAL SOCIETY OF WESTERN AUSTRALIA PATRON Her Majesty the Queen VICE-PATRON His Excellency Major-General Sir Douglas Kendrew, K.C.M.G., C.B., C.B.E., D.S.O., Governor of Western Australia COUNCIL 1970-1971 President Vice-President Past President Joint Hon. Secretaries Hon. Treasurer Hon. Librarian Hon. Editor B. J. Grieve, M.Sc., Ph.D., D.I.C., F.L.S. G. M. Storr, B.Sc., Ph.D. P. E. Playford, B.Sc., Ph.D. B. Ingram, B.Sc. (Hons.) P, G. Wilson, M.Sc. R. N. Hilton, M.A. Ariadna Neumann, B.A. A. S. George, B.A. S. D. Bradshaw, B.Sc. (Hons.), Ph.D. S. J. Curry, B.Sc. A. B. Hatch, M.Sc., Dip.For. J. H. Lord, B.Sc. D. C. Lowry, M.Sc. A. J. McComb, M.Sc., Ph.D. D. Merrilees, B.Sc., Ph.D. R. T. Prider, B.Sc., Ph.D., M.Aust.I.M.M., F.G.S. 4. — A new pedunculate barnacle, Paralepas georgei sp. nov. (Crustacea: Cirripedia-Thoracica) epizoic on Australian spiny lobsters and crabs By A. Daniel* Communicated by R. W. George Manuscript received 22 July 1969; accepted 16 Septem'ber 1969 Abstract Paralepas georgei, a new species collected in 40- 80 fathoms off the southern and lower west coast of Australia, is described and discussed. Distinctive features inciude scuta and a carinal keel, and a distinct pectination of the mandible. Introduction During a visit to the Western Australian Museum, Perth, in 1962, opportunity availed for examining a small collection of Cirripedes, epi- zoic on crustaceans, which was taken for detail- ed study. This material included a new species of the genus Paralepas epizoic on lobsters and crabs. SUBORDER LEPADOMORPHA. Pilsbry 1916. Family Heteralepadidae Nilsson-Cantell, 1921. Genus Paralepas, Pilsbry. 1907. Paralepas georgei sp. nov. ‘Figs. 1-10) Material examined: Holotype: WAM 190-62 taken from PanuUrus cygnus George off Rott- nest I.. Western Australia i32"00'S, 115°30'E) fishing boat Gloria, 3.II.62. Paratypes: Three specimens WAM 226-68 taken from P. cygnus oif Rottnest I. (32°00'S, 115'’30'E) fishing boat Gloria, 3.II.62. Ten specimens WAM 191-62 (5 specimens* and ZSI Cl '5 specimens* taken from Jasus novaehollandiae Holthuis, Swan I., Tasmania (40°44'S, 148‘’06'E> M. Olsen. 10.VIII.62. Two specimens WAM 193-62 taken from Pseudocarcinus gigas (Lamarck) off Doubtful I. Bay, Western Australia <34°22'S, 119°36'E) 1.XI.59. 40-60 metres. Twenty-one specimens WAM 196-62 taken from Hvpothalassia armata (de Haan> 16 km. west of Rottnest I. (32^00'S, 115°30^E* K. Sheard, 22.IV.54, approx. 80 m. Distribution: The above records indicate that this species of pedunculate barnacle lives in moderately deep shelf waters on the southern and lower western coasts of Australia. It is also possible that the “Lepas” mentioned by Rathbun (1923 ; 104) on Pseudocarcinus gigas from Bass Strait and in the Great Australian Bight, 80-450 fathoms, also belong to Paralepas georgei. Diagnosis: Capitulum swollen, cuticle strongly thickened, orifice crenulated, with distinct elon- gated scuta and carinal keel. Labrum bullate, crest hairless supporting sharp teeth, mandible with four teeth, lower and upper margins of all * Zoological Survey of India. Calcutta. four teeth (excepting upper margin of first) supporting several strong spines; first maxilla with cutting edge deeply notched, the smaller portion above notch armed with one strong spine followed by two smaller pectinated spines and the lower free margin with two large pec- tinated spines interspersed with paired thin spines; second maxilla elongated, superior mar- gin with group of long setae and inferior margin with short setae. Cirri short, slightly curved with long pedicels. Each segment of cirri ii-vi with lesser curvature bearing semicircle of long and slender spines below' the articulation and greater curvature bearing a semicircle of stout claw-like spines at articulation. Lesser curva- ture of each segment of cirri iv-vi with a pair of spinuies in addition to semicircular whorl of spines. Single large filamentary appendage present at base of first cirrus. Penis distinctly annulated with minute rivet-like structures. Size: The largest specimen in the collection has a capitular length of 18 mm. and a bi’eadth of 10 mm. with the peduncle measuring 8 mm. in length and 3 mm. in breadth. The measure- ments of the capitulum and the peduncle in the material examined are given in the following table: — TABLE 1 (.■aj)itulum Poduncle Scries l.eiifjth Breadth Lenjjth Breadtli in nun. in inni. in inin. in nini. 1 .... 10 S-IO 3 2 12 9 10 3 ~i 11 X, 9 10 3 4 10 7 7 3 5 9 7 3 3 () X 5..5--0 2-6 1 . r,-3 7 7 5 6 3 H () 4-5 2-3 1 .5-2 9 5 3 . 5-ry 1 .r>-3.5 1.5-3 10 4 3 2-4 2-3 11 3 2 2-4 2-3 Description: The capitulum is extremely vari- able in shape. In some individuals it is latei'- ally ovoid wdth smooth surface, and has a strongly arched carinal margin, and a moder- ately arched occludent margin which is inter- rupted by highly pi’otuberant crenulated lips of slit-like orifice. The orifice extends to one- fourth the capitular length and the crenulations nm inwards as distinct furrows (Fig. 1). In 33 Figures 1-10. Paralepas georgei sp. nov. 1, 2. — Entire animal, side view. 3. — Labrum with palp. 4. — Mandible. 5. — First maxilla. 6. — Second maxilla. 7. — Two segments of third cirrus. 8. — Two segments of fifth cirrus. 9. — Base of first cirrus with filamentary appendages. 10. — A few segments of penis with rivet-like structures. 34 some others (probably young forms) both the occludent and carinal margins are moderately arched, the former interrupted by a less pro- tuberant orifice which extends to one-third capitular length. The lips of orifice are faintly crenulated and the crenulations slant towards base. In another series of specimens there are irregular folds on the surface with faint crenu- lations near the orifice. The occludent and carinal margins of the capitulum are arched equally with the occludent margin sloping into margin of orifice without interruption. The orifice is wider reaching more than one-third capitular length and capitular apex is acutely pointed (Fig. 2) . In all specimens the capitulum is greatly swollen, cuticle is strongly thickened with an inner layer of transverse muscle fibres and the orifice is slit-like, with the lips crenulated. There is a distinct carinal keel and distinct though reduced scutal plate just below the orifice. Mouth Parts: The lahrum (Fig. 3i is bullate with 30 to 40 sharp teeth borne on the hairless crest. The number of teeth varies according to the size of individuals, large specimens having more teeth. The palp is provided 'Pig. 3> with several long and soft setae on inner margin. The mandible (Pig. 4i bears four teeth includ- ing the inferior angle. The lower margins of all four teeth and upper margins of 2nd, 3rd and 4th teeth are armed with several strong spines. The superior and inferior margins of the mandible bear numerous long and thin hair-like setae. Several rows of short and stout or long and thin spines occur near superior and inferior angles of the mandible. Spines also occur in groups or singly at the mid-region of the mandible. The first maxilla (Fig. 5) is divided by a prominent notch; the superior portion which is slightly less than one-third the total length of the free cutting edge bears an upper central strong smooth spine and two pec- tinated spines. The notch supports a few thin spines. Below the notch the cutting edge bears two major pectinated spines (equal in size to the smaller spines of the tridentate group above), interspersed with paired thin spines. The surface is clothed with numerous slender spinules and few teeth arranged in groups and rows. The superior and inferior margins bear numerous long spinules. The second maxilla (Fig. 6) is elongated, its superior margin sup- porting a gi'oup of long setae and inferior mar- gin supporting slightly shorter setae; the space between these two groups bear 7-9 sharp teeth. Cirri: The cirri are all short, and only slightly curled. The pedicels of all cirri are rather long. The number of segments in the rami of the cirri in the specimens examined is as follows: — Cirrus i-9-10. 7-8; Cirrus ii-13-14. 15-16; Cirrus iii-15-16. 15-16; Cirrus iv-15-16. 16-17; Cirrus v-14-15, 17-18; Cirrus vi-14-16, 17-18. The first cirrus is inserted very near the mouth and is separate from the second cirrus. The inner rami of the first cirrus is nearly half as broad again and slightly longer than the outer rami. Both rami are densely armed with whorls of slender plumose spines. The spines of the basal segments are straight and are plumose on both sides. The spines of the distal segments are slightly curved with the greater curvature being plumose. The cirri ii to vi are nearly equal in length. The inner rami of cirri ii and iii are slightly broader than the outer rami, while in the cirri iv to vi the rami are nearly equal in width. Each segment of the cirri ii to vi exhibits the armature typical of the sugenus Paralepas. The lesser curvature of the segments support a semi- circle of long and slender spines (the longest pair of spines being plumose on one side) below articulation (Fig. 7>. In cirri iv to vi. in addi- tion to these spines, each segment bears a pair of spinules below the semicircular whorl of spines (Fig. 8). The greater curvature of the seg- ments of cirri ii to vi supports at each articula- tion a semi-circle of stout. cla>v-like spines. At the base of the first cirrus there is a single large filamentary appendage (Fig. 9). At the base of the sixth cirrus there is a caudal appen- dage: it has seven to twelve segments and is a little longer than the protopodite of the sixth cirrus. The penis is long, tapering, distinctly annulated, has minute, rivet-like structures placed along its length (Pig. 10 1 , and also bears long setae and short spines scattered over sur- face and at tip. Remarks: Newsman (I960) following the sug- gestions of Pil&bry ( 1907 ) , Annandale (1909) and Broch (1922) raised the subgenera Heteralepas Pilsbry and Paralepas Pilsbry to the generic level. The genus Paralepas Pilsbry is consid- ered to include the following valid species and forms: P. dannevigi (Broch. 1922), P. distincta (Utincmi. 1949), P. globosa (Hiro, 1936), P. in- termedia (Hoek, 1907), P. lithotryae (Hoek, 1907 ). P. mviuta (.Phillipi, 1836) and subspecies americana (Pilsbry, 1953 >, P. morula (Hoek. 1907), P. nodulosa (Broch, 1922), P. palinuri (Barnard, 1924* and subspecies urae (Newman, I960), P. pedunculata (Hoek, 1883), P. peri- carinata iPilbsry. 1907'. P. reticulata (Annan- dale, 1914), P. rosea (Hiro. 1938), P. tuberosa (Nilsson-Cantell, 1932), P. xe7iophorae (Annan- dale, 1906), and P. scyllarusi Utinomi, 1967. The present species can be separated from all these species excepting P. daiinevigi (Broch) by the presence of both scuta and a carinal keel. P. damievigi (Broch) which also possesses a pronounced carinal keel and chitinous scuta occurs in deep water on gastropods and differs conspicuously in the mandible being armed with small denticles on the lower side of the third tooth only, the maxilla having a relatively lesser pronounced notch with strong spine at upper edge and the penis with a tuft of hairs at the distal end and a few rather short hairs on sides. The present species resembles P. palinuri urae Newman (1960. fig. 6 G.), P. distincta Utinomi (1949, fig. 2 D). P. lithotryae Hoek (1907, pi. ix. figs. 8-8') and P. scyllarusi Utinomi (1967, fig. 2 d) by the possession of a broad tapering and coarsely annulated penis which is furnished with many rivet-like structures. The present forms differ conspicuously from all the known species of Paralepas in the dis- tinct pectination of the mandible i.e., the lower 35 margins of all four teeth and upper margin of 2nd, 3rd and 4th teeth supporting several strong spines, several rows of short and stout or long and thin spines occurring near superior and inferior angles and also the occurrence of spines in groups or singly at the midregion of the mandible. The first maxilla also is distinct by the possession of an upper central smooth strong spine and two smaller pectinated spines below, with the deep notch supporting a few thin species and cutting edge below notch bear- ing two large spines which are pectinated and surface of maxilla clothed wdth numerous slen- der spines and few^ teeth arranged in groups and rows. The lesser curvature of each seg- ment of cirri iv-vi. in addition to supporting a semicircle of long and slender spines . A second pulse arriving within this time interval would be recorded by the electronic scaler (total counts) and on the ‘thorium pairs’ I’egister. Before the total a-activity and the thorium and uranium concentrations could be calculated, where applicable, it was necessary to know the mean atomic number Z (Turner, Radley and Mayneord, 1958 > and mean atomic weight W (Cherry, 1963) of the sample material. In the case of wheat ashes a combination of wet chemical and X-ray fluorescence analysis was used to obtain Z and W, and for the parent rocks these values were calculated from pub- lished analyses of similar rock types (Mason, 1958). For many Western Australian soils, major element analysis has shown that there is an excellent correlation between Z or W and the iron and calcium content of the soil. For these soils therefore, calcium and iron were measured by flame emission and absorption techniques respectively and the corresponding values of Z and W were determined. Exchangeable calcium was measured using molar NHiCl to displace the calcium which was then determined on the S.P. 900 flame photometer. The major clay and accessory minerals in the < 2/a fraction were analysed qualitatively using a Phillips X-ray powder diffractometer. Full details of these analyses will be presented in a later publication. Calculation of o-activity The total a-activity in curies per gram (Ci/g) of each sample was calculated from the equation developed by Turner et. al. (1958), and is given by A = . (t -4 X 10 11 Ci/g (1) T R„.A.7/ where C ^ counts/hour above background Rq - a -particle range iii cm. of standard air. A -1 area of sample in cm“. For unweatbered rocks, in order to calculate the concentrations of uranium and thorium from the pairs counts it was necessary to allow for the chance occurrence of ‘spurious pairs'. This correction was carried out from the equation proposed by Cherry (1963) where the spurious pairs rate S is given by 8 = . r exp (^- X,.r) (2) where again C total count rate and r “ dead time of the register circuit The half life correction, as discussed by Cherry was applied to the corrected pairs rate to obtain a final value, P. for the pairs rate, in this case disintegrations occurring in two half lives were measured, yielding | of the total ■pair’ disintegrations, therefore the half life correction factor was 1.333. Having determined the pairs rate P and the total a-count rate C (both in counts/hr) the thorium and uranium concentrations in p.p.m. for the rock samples were calculated from the equations C = \\A . A ((Mo5 U + 0-U434 Tli) (3) where A area of sample W means atomic weight of sample The derivation and limitations of equations (3) and (4> have been fully discussed by Cherry (1963). For the soils and ashed wheats, as previously discussed, equations (3) and (4) do not apply C and for these samples — ratios have been cal- P culated instead. Tables 1, 2 and 3 list these results for soil, ashed wheat and rocks respectively. 39 so r 70 eo 50 40 30 20 ^ i o 10 ^ LEGEND : O - WHEAT ASH : VARIETY GAMENYA • - WHEAT ASH : OTHER VARCTIES. ▲ - BARLEY ASH 10 20 30 40 WHEAT ASH TOTAL ^-ACTIVITY 50 80 70 PICOCURIES PER GRAM. 80 90 100 Figure 2. — Correlation of wheat-ash and soil cc-activity. 2 PE RCENT F9 + Al. b 10 _j 15 Figure 3. — Correlation of soil cc-activity with per cent. Fe + Al. 3a. — Total cc-activity of soils formed on the Pre-Cambrian Shield of Western Australia: • = soils of lateritic origin: o = other soils. 3b. — Total cc-activity of soils formed on Mesozoic and Cainozoic sediments. 40 Experimental results and discussion From the data presented in Tables 1, 2 and 3 the following points were noted. (i) Soils and wheats from the western part of the Precambrian shield w^ere in general much more active than those from other localities measured in this survey, and elsewhere. (ii) Although the ashed wheat activities were obviously dependent on the activity of the soil on which they were growing, Pig. 2. the cor- relation was much poorer than expected. This can be partially explained by the wide variation in uptake of a-emitting isotopes by wheats of different varieties as showm in Table 2 for site 10 at Wongan Hills. For these seven w^heats, growing on the same soil there was a three-fold increase in the ash activity from the lowest to the highest respectively. (hi) It has been stated that thorium tends to accumulate with sesquioxides of iron and alum- inium (Talibudeen, 1964). Considerable difficulty was experienced in quantitatively extracting these sesquioxides from the soil samples and therefore a correlation w'as attempted between total a-activity and the sum of total iron and aluminium as measured on the atomic absorp- tion spectrophotometer. The results are showm in Pig. 3. For those soils which are mainly of lateritic origin (closed circles Pig. 3a) there is a linear correlation, how'ever in the second group (open circles Fig. 3a) the association between a-activity and percent Fe -j- A1 is not as obvious. All the soils in this group are fine textured, therefore much of the aluminium will be pre- sent in the clay fraction rather than as sesquioxide. In addition, most of these soils contain finely divided fresh rock fragments and several w^ere formed on or near basic dolerite intrusions which would contribute to the high A1 and Fe contents without a proportionate increase in total a-activity. For the soils formed on Cainozoic and Meso- zoic sediments the total a-activity is approxi- mately proportional to the logarithm of the percent Fe i- Al. This departure from linearity may be explained in a similar way, in that the more active soils contain a higher proportion of clay which in turn contains appreciable amounts of aluminium. (iv) For soils formed on the Precambrian shield the a-activity levels of the sand and gravel components were often higher than the finer fractions as shown in Fig. 4a, where there is a definite negative correlation between total soil activity and percent soil passing a 120 mesh sieve. The soils formed on Cainozoic and Meso- zoic sediments are by contrast low' in a-activity and tend to exhibit a positive correlation with percent soil passing a 120 mesh sieve (Pig. 4b). Two soils from sites 18 and 19 (open circles Fig. 4a) do not fit this general scheme. Although formed on Precambrian granite rock and of coarse texture they are extremely low in a-activity. The soils at both of these sites have undergone severe leaching and consist mainly of coarse grains w^hich apparently cannot i*e- tain active isotopes. For the five samples listed in Table 4 the gravel activity A^ was measured separately and the activity of the remainder of the sample Ak was calculated from the equation: ^ ~ (5) where At ■ total activity of the sample ^ weight fraction of gravel. Figure 4— Correlation of soil cc-activity with particle size. 4a.— Total cc-activity of soils formed on the Pre Cambrian Shield of Western Australia: o = samples from sites 18 and 19. 4b.— Total cc-activitv of soil*? on Mesozoic Cainozoic sediments. ^ 41 TABLE 1 Table 1. — Total ct"^ctivity of surface and sub-soil samplss.t Site No. and Location I Sam[)le No. Depth Sampled Gravel o/ /o Geolugieal Substrate Total a - activity C Miinseil Colour 1 pCi/g 1. Irwin J .1 0-12" 0 M.S.* ** 20 23 7.5 vr 4/2 2_ Irwin 2.1 0-7" 0 M.S. M 22 10 vr 4/1 2.2 7-20" 0 M.S. t 30 10 vr 0/3 3. (Jreenough 3.1 0-12" 0 M.S. 4 24 10 yr 3/3 3.2 12-20" 1 M.S. 3 22 5 yr 0/3 4. Kradu 4.1 0-5" 0 M.S. 11 20 2.5 vr 4/4 4.2 5- 15" 0 M.S. 10 34 2.5 yr 5/0 4.3 15-20" 0 M.S. 13 20 2 . 5 vr 5/0 i). Kradii 5.1 0-4" 0 M.S. 10 24 10 yr 0/2 5.2 4-20" 0 M.S. 13 20 7.5 yr 0/0 6. Tenimiewa .... 0.1 0-0" 3 M.S. 10 20 2.5 yr 3/0 0.2 0-24" 4 M.S. 10 17 2.5 yr :i/s Pindar 7.1 0-0" 10 AM. 27 33 10 yr 0/4 7.2 0-20" 00 AM. 75 29 10 vr 7/0 7.2.5+^ 0 20" A. a. 81 17 8. Caima 8.1 0-4" 8 A.S. 19 10 5 yr 4/0 8.2 4-10" 29 A.S. 25 20 2.5 vr 3/0 8.2.5 4-10" A.S. 40 10 0. Wongan Hills 9.1 0-4" () A.G. 19 22 2.5 yr 0/2 Sani])led Ang. ’00 9.2 4-12" 8 A.a. 19 20 2.5 yr 7/4 9.3 12-17" 41 A.G. 37 28 9.4.3 12-17" A.G. 45 19 Sampled Nov. ‘00 9.0 0-4" A.G. 18 20 9.7 4-12" A.G. 20 26 9.8 12-17" A.G. 34 20 9.9 0 4" A.(t. 55 Sam))led Nov. ’05 9 . 1 0 4 -8" A.a. 34 10 yr 7/2 10. M'ongan Hills 10.1 0-5" 10 AM. 60 20 10.2 4-10" 20 A.G. 70 10 10.2.2 4-10" A.G. 00 24 10.2.5 4-1 0" A.G. S3 16 10.3 10-20" 47 A.G. 00 29 2.5 vr 5/6 10.4 0 4" A.G. 85 12 10.5 4-S" A.G. 95 15 10.6.5 Surface Gravel A.G. 172 15 11. Calingiri 11 .1 0-4" 45 Dolerite 29 20 2 . 5 yr 5/ 4 11.1.5 0-4" I *> Borden 22.1 0-0" 0 A.S. 5 18 5 yr 5/3 ^ >9. 9. 0-14" 0 A.S. 5 20 10 vr 7/3 22 3 14-24" 0 A.S. 12 10 2.5 yr 4/0 23. Borden 23.1 0-3" 9 A.S. 0 22 5 vr 3/4 23.2 3 - 1 2" 2 A.S. 11 13 2.5 vr 3/4 23 . 3 12-10" 2 A.S. 0 12 7.5 yr 7/0 24. Albany ! 24.1 0 4" 44 M.S. 17 22 10 yr 5/1 ! 24.2 4-10" 76 .M.S. 40 17 10 yr 7/3 24.2.5 4-10" MS. 30 23 * M.S. =s Mesozoic and fainozoic^ marine sediments. A.S. = Archaean Sediments with l)asic igneous intrnsives. A.t». - Archaean granite. ** Sample number witli two digits only, were jtrepared by grinding to pass a 120 mesh sieve. Third digit ^ 2<^ ‘lf> fraction. '.i mottles separated and ground. 5 gravel separated and ground. t The exact locations of the above samples sites are available from the authors. 42 TABLE 1 (Continued) Table 1. — Total ^-activity of surface and sub-soil samples.! Site No. and i,ocation Sample No. Depth Sani])led Oravel o/ Geologieal Substrate Total a - activity c. Mim.sell Colour p('i/K 24.3 16-26" 16 M.S. 57 27 10 \T 6/6 25. Jarrahwood . . 25.1 0-6" 0 M.S. 5 22 10 yr 7/1 6-15" 17 M.S. 14 17 2.5 yr 7/2 25.3 15-30" 53 M.S. 18 67 26. Capel 26.1 0-24" M.S. 52 34. Wongan Hills 34.1 0-4" () A.O. 51 7 34.2 4 S" 0 AM. 17 21 34.3 8- 1 6" 43 AM. 49 17 35. Wongan Hills 35.1 0- 4" 47 \.(i. 56 17 35.2 4-8" 79 AAi. 94 29 60. (’orrigin .... .. . 60.1 0-3" 42 A.O. 101 61. ('orrigin 61.1 25-24" 65 A.<;. 2S2 62. York 62 1 0-2" A. (4. 39 62.2 2-8" A. (4. 46 + The exact locations of the above saini)les sites are available from the authors. The last column of Table 4 lists the ratio Ac. — , from which it can be seen that the gravel Ar fraction was generally higher in activity than the remainder. Sample 24.2 was an exception; however in this sample the coarse material mainly consisted of rounded pieces of magnetic haematite, in contrast to the concretionary ironstone gravels in the other samples. For these ironstone gravels the uranium pairs C count rate was negligible and the — ratios were P in the range 15-17 which is characteristic of the Th’^-^^ decay series in equilibrium. Some caution must be exercised in interpreting these C — ratios however, because recent experiments, P using a new counting technique to determine true pairs directly, indicate that the Poisson distribution used by Cherry (1963) over estimates the spurious pairs at high count rates. Further work is required before a better correction can be established with any degree of precision. (v) The contribution from superphosphate application to the total a-activity of a soil was estimated from measurements of the activity of eight batches of superphosphate produced by CS-BP and CRESCO, the two leading distribu- tors in Western Australia (Table 3). A mean for the superphosphate activity was 63 pCi/g and for a typical application rate (180 Ibs/acre) the increase in soil activity at the surface would be 30 pCi/sampling area (250 cm-). If, for example, as the result of ploughing or leaching, this activity was distributed through only the top 10 cm of soil, then the increase in soil activity w^ould be of the order 0.01 pCi/g. The general conclusion may be reached then, that even prolonged applications of superphosphate fertiliser at high rates will not cause a measur- able increase in soil a-activity. At Wongan Hills, sites 9 and 10, a comparison of soils which had received heavy applications of superphosphate (samples 9.1, 9.2, 9.3, 10.1. 10.2, 10.3) and of the same soils which had received no superphosphate (samples 9.6, 9.7, 9.8. 10.4, 10.5) showed the activity levels to be comparable or even higher in the unsupered soils, thus supporting this general conclusion. A possible exception was encountered at site 11, Calingiri, where a shallow clay-loam soil has developed directly on a dolerite dyke. In this soil, activity levels of approximately 30 pCi/g were encountered whereas the activity of the TABLE 2 Table 2. — Total ^.-activity of ashed wheat and barley. Site No. and Location Wheat Variety Total a-activitv pCVfJ C P 1. Irwin •> 2s. xVungarin Insignia 2 43 33 27. Hcncublihi 4 30. Morawa . . Falcon 2 14 31. Nortliamrtton . .. Mengarvie 1 21 32. Northampton . . (4amema <1 23 33. Lake King 9 33 60. Corrigin 69 * hurley Ash. 43 TABLE 3 Table 3. — Total ^-activity of rocks and superphosphate. Site, location or Source Sami»le Total «-activit y ]'<'i/K ‘ P U ppm Th ppm 9. Woiii'an Hills Arcliaean (>;') 34 12 40 1 1 . ( 'a!in}j:iri (iranite Dolerite 4 24 <) 3 I(>. Xor^cmaii ... Archaean 7 40 ^1 4 IS. Ks|i(*rancp (tiadss Proterozoic ;')9 21 4 ()0 '2i. Alliaiiv (iranite Piniest<> 33 banv CS HP. JVrtli CS ]}p. Perth TO •(>■) 71 72 2() 34 CS It P, Perth ■()0 ’•)(> 54 24 parent dolerite was only 4 pCi/g. Here it would seem that one or more components in the soil has the ability to ‘fix’ a-active isotopes from the applied superphosphate. The increasing use of highly active Florida rock phosphate in Western Australian super- phosphates from 1966-67 onwards may clarify this situation for subsequent samplings. (vi> at site 9. Wongan Hills, a series of soil measurements at yearly intervals since 1965 has indicated that the rate of movement of a-active isotopes through the soil profile may be much faster than is generally supposed. Topsoil and subsoil taken late in 1965 whilst the site was in crop were quite active, 55 pCi/g and 34 pCi/g for the 0-4 in. and 4-8 in. sample respectively (samples 9.9 and 9.10) which are comparable with values measured by Marsden (private com- munication), After lying fallow for a year the TABLE 4 Table 4.— Comparison of total ^-activity of the whole soil with that of the gravel component. Weit'lit 'Potal ( • ravel Remainder A .Fraction Activitv Activity Activitv a Sani])le (i ravel A A A A X T a K R (1 (pc'i/a) (i>< ’i/K) 7.2 0.0») 81 83 78 1 .1 8.2 0.29 27 41 22 1 .9 10.2 0 . 3.5 71 80 03 1 .4 12.2 0.50 45 .54 .33 1 .7 24.2 0.78 43 33 78 0.4 site was re-sampled in 1966 and again in 1967. For these samples (9.1, 9.2, 9.3) there was a significant decrease in surface activity. However, at a depth which coincided with a zone of soft iron concretions and clay mottlings the activity was again quite high. The inference then, is that ploughing throws active materials into the surface soil and this subsequently leaches back to the sesquioxide horizon. Ihirther detailed sampling will be required to confirm this point. (vii) From the measurements of a-activity made so far, it is difficult to make conclusive statements regarding the effects of climate and rainfall, however, the following observations appear to be pertinent. On an easterly transect through York, Keller- berrin. Merredin and Southern Cross to Bulong and Norseman there is a steady decrease in mean rainfall from 18-20 in. to 9-10 in. East- wards as far as Merredin, which lies close to the 12 in. isohyet, the dominant soils are coarse textured yellowish loamy sands with much iron- stone gravel, and the soil a-activity is reason- ably constant in the range 45-50 pCi/g. Further eastwards the activity diminishes sharply to 2-10 pCi/g (Bulong and Norseman) and the soil becomes a finer textured gravel- free reddish clay-loam with a much more uniform distribution of iron through the profile. Therefore it would appear from the present results that when the mean annual rainfall is sufficient to cause waterlogging in winter and favour gravel formation then there is also a concentration of a-active isotopes. Further south, at Esperance and Dalyup in the 25 in. rainfall belt, with a more uniform distribution of rainfall throughout the year the soils are more severely leached, contain negli- gible amounts of Pe and A1 and are extremely low in activity. Conclusions Lateritic soils formed on the Precambrian shield of Western Australia are unusually high in natural a-activity and there is a definite association between activity levels and the ironstone gravel content of the soils. For these soils there is also a significant correlation be- tween activity and Fe -{- A1 content. Some of the active isotopes present in the soil are readily taken up by wheat, however the rate of uptake varies widely with variety. Although supei-phosphate fertiliser is high in natural a-activity it is unlikely at normal appli- cation rates to have made a significant contri- bution to the total soil activity. There is some evidence that leaching of active isotopes through the soil profile may be quite rapid in regions of adequate rainfall and there appears to be an association between soil activity levels and rainfall and climate. Acknowledgements The authors wish to acknowledge the financial support received for this project from the Soil Fertility Fund of W.A. and the Australian In- stitute of Nuclear Science and Engineering. They 44 also are grateful to Dr. R. Fry and Mr. N. Conway of the Australian Atomic Energy Com- mission for permission to use their low level scintillation a-detector, and for much helpful advice and discussion. Mason, B. (1958). — ‘Principles of Geochemistry’ 2nd Ed. (John Wiley and Sons Inc., New York). Mayneord, W. V., Turner, R. C. and Radley, J. M. (1960). — Nature, Lond. 187: 208. Talibudeen, O. (1964). — Soils Fertil. Harpenden 27: 347. References Cherry, R. D. (1963). — Geochim. Cosmochim. Acta 183. Marsden. E. (1959). — Nature, Lond. 183: 924. (1960). — Nature, Lond. 187: 192. (1961).— Nature, Lond. 189: 326. Turner, R. C., Radley, J. M. and Mayneord, W. V. (1958).— Rr. J. Radiol,, 31: 397. Zymlowska, S. and Ostrowska, A (1965). — Roczniki glchozn. 13: 203 Zymlowska, A. and Wilgain, S (1961). — Nukleonika. 6: 813. 45 6. — Notes on the Flora and Vegetation of the Nullarbor Plain at Forrest, W.A. By E. R. L. Johnson* and A. M. Bairdi' Majiuscript- received J8 March, 1969: accepted 17 Fehrunry. 1970 Abstract Brief collecting trips to Forrest in the centre of the Nullarbor Plain were made in 1930 and 1955. years in which above average rainfall had resulted in exceptionally rich development of the herbaceous flora. One hundred and five species of flowering plants were collected, of which twenty-two were introduced. The flora is composed mainly of taxa which are common to the floras of the drier inland regions to the west and east of the Nullarbor Plain. A few only extend further to the south west and south east into regions with higher rainfall. Domiiiant families are Chenopodiaceae, Asteraceae and Poaceae which. In addition to having the largest number of species, more than half the total, also produce an abundance of In- dividual plants. Introduced plants were not abundant and were foiind only near the railway line and aerodrome. The representation of families is typical of the Eremaea and in contrast with that of the south western corner with its abundance of Myrtaceae, Proteaceae and Epacridaceae. The vegetation is described under the head- ings: plain, depressions and tree belt. The greatest number of species was foxind in the 'dongas”, broad shallow depressions which had a few large shi'ubs usually Acacia oswaldii. Erevjophila longifoUa and Pitiosporum phylli- raeoides', clumps of low perennials and a seas- onal ground cover of grasses and herbaceous dicotyledons. On the main level of the Plain the open dwarf shnib community of Kochia sedi- folia, the “bluebush” characteristic of the Nul- larbor Plain, was seen in healthy condition in 1955, only In restricted areas. In many places old dead stems were all that remained, with the shorter lived Bassias forming the sparse ground cover. A belt of Myall trees (Acacia sowdenii), 14 miles north of Forrest, was in poor condition in 1955 with most of the trees dead. The general impression in the area Is of a perennial vegetation near the limit of tolerance of the arid climate, and unable to withstand the additional pressure of rabbit grazing. Introduction The Nullarbor Plain, that vast featureless stretch of country lying north of the Great Australian Bight (fig. 1) has been known since early days of exploration, and since 1917 has become familiar to the thousands of travellers on the trans-continental railway. Nevertheless there is no detailed botanical description of the central Nullarbor. It is an arid area with average annual rainfall between 6 and 7 inches (160 mms) and shade temperatures wdiich may exceed llO^F in any of the summer months (but there is no shade on the Plain!). Geologically it forms part of the Eucla basin of horizontally bedded tertiary (Miocene) limestone and the soil is shallow, reddish calcareous loam. * C/o State Herbarium of South Australia. North Ter- race, Adelaide. S.A. 5000. i Botany Dept., University of Western Australia. Ned- lands, W.A. 6009. Early explorers described it as a “dreary waste” and “stony waterless desert” and most of them were content to journey around its edges. How'ever, Tate (1879), while searching for artesian water, went inland about 33 miles from Eucla and reached its southern part. He noted the sparseness of the vegetation and that species were few'. Willis (1959), in an account of explorers and collectors in the Eucla region, mentions Delisser (1861 and 1865), Batt (1886-1896) and Kemsley (1952) as having col- lected plants from parts of the Plain, Willis w'ith the Russell Grimw’ade expedition. 1954, collected betw'een the head of the Bight and Madura. Anketell in 1901. when a member of Muirs Trans-Australian Railw^ay Survey Team, collected 22 species (now' in the Western Austra- lian Herbarium > . As localities w^ere not at- tached to some of these, it is doubtful how many were found on the Plain. In South Australia a number of collections have been made on the eastern edge of the Plain near Ooldea by Capt. A. S. White < Black 1917), Cannon (1921). Black (1921). Ising (1921), Adamson and Osborn (1922) and on the Plain at Hughes, 32 miles east of the Western Aus- tralian border, by Ising (1920). Adamson and Osborn described the vegetation of the Nullar- bor Plain as shrub steppe whth Kocfiia sedifoUa and Atriplex vesicaria as the principal shrubs. They also described the vegetation of the “dongas”, a term of South African origin which has been accepted in the literature and in local usage for depressions scattered throughout the Plain. Forrest, lat. 30.5 S. long. 128.06 E. lies in the centre of the Plain and therefore, as far as the flora is concerned, should show a minimum of influence from surrounding regions. The authors visited this locality for 3 days in Octo- ber, 1955. in the expectation of seeing the her- baceous vegetation in good condition after above average rains. An equally brief trip had been undertaken in 1930. so there w’as interest in comparing the vegetation 25 years later. The photographs and descriptions are of the vegeta- tion as seen in 1955 except where the early visit is specified. Collecting w'as done within easy walking distance of the aerodrome and railw^ay and on trips by truck north and south of the line w'hich gave a cross section nearly 30 miles long (sketch map. fig. 2>. The first impression of the vast flat Plain stretching unbroken to the horizon is unforget- table. The flatness is, how^ever. relative and in detail the Plain is undulating and with widely scattered depressions of varying extent and depth. Several of these were visited and also a belt of trees about 14 miles north. 46 128° OO' I 128° 15 ’ I I I 0 5 10 Rainfall Annual rainfall for the 30 years between 1925 and 1955 (fig. 3) demonstrates the great varia- bility; totals in this period ranging from 2 to 16^ inches. The published average for 50 years to 1965 is 6.5 inches. The average monthly rainfall is almost the same for each month of the year (fig. 4) but this indicates only that rain may fall in any month; the actual falls in any one year are very unevenly dis- tributed. The seasonal distribution and the way in which the rain falls is important to the vegeta- tion not only for germination and maintenance of growth but also in the location of available moisture. Heavy downpours on dry ground mean run off and accumulation at lower levels; dongas may become lakes. After 6 inches of rain in February, 1930, a lake 3 miles across formed 13 miles west of Forrest and persisted for several weeks. Repeated light falls with little or no run off are of greater benefit to the higher levels of the Plain with its bluebush comimunity. In general, summer rains tend Figure 2.— Sketch showing tracks running N and 3 and approximate position of localities visited in relation to the railway line and aerodrome MILES 47 YEARS 1926-55 Figure 3. — Annual rainfall at Forrest for a 30 year period. to come in heavy downpours, often causing flooding, while winter rains are usually lighter, more frequent falls. For the years in which collections were made, 1955 can be seen as the second year of above average rain after a period of drought and 1930 as a quite exceptional high after a long and extreme drought. Vegetation Plain. The higher levels of the Plain carry the characteristic shrub steppe with the bluebush Kochia sedifolia as the dominant and almost the only perennial. The condition of the blue- bush varied in different areas and over much of the Plain all that remained were long per- sistent dead stems. One such area (fig. 6A> was examined about 1-2 miles to the N.E. of the airport beyond a big donga. The plain here appeared to be the same in all directions as far as the eye could see except tow-ards the donga. The soil was shallow reddish loam over travertine limestone W’hich outcropped and lay in broken fragments on the ground. Lichens encrusted the rock (fig. 5 & fig. 6A) and also occurred on some of the bare ground. No living bluebushes were found: the dead bushes, as by notebook in figure 6A. showed the pattern of the original bluebush steppe. There w'as a marked tendency for concentration of annuals against these old plants. The ground cover was relatively sparse with bassias particularly Bassia patenticuspis and B. uniflora predomin- ating (fig. 6A). Several different periods of origin were indicated by their differences in size which ranged from relatively woody small bushes to single stemmed seedlings. Two small composites Angianthus brachypappus and Gnephosis skirrophora also contributed to the ground cover. Other areas of high plain were seen on the trips to the north and south. To the north there were two areas where the bluebushes had compact foliage and few projecting dead stems (fig. 6B). Angianthus in full bloom formed a conspicuous ground cover. The track going for 12 miles south of the line crossed areas in which there were very open stands of bluebush inter- mixed with sparse tufts of Stipa nitida. Again Bassia spp and Angianthus were the main com- ponents of the sparse ground cover. Similar mixed stands of Kochia and Stipa were also seen beyond the 12 mile donga. The dongas. Shrubs or small trees show from a distance the presence of a donga. In this flatness anything more than 3 feet high is con- spicuous on the skyline. Vegetation of the dongas varies with size, depth and depth of soil but species of Acacia, Ereiyiophila and Pittos- porum phylliraeoides are the usual tall shrubs with patches of perennial chenopods other than Kochia sedifolia and, after rain, a lush herba- ceous growth. Three big dongas were examined. The first (Di on species listi at the N.E. corner of the aerodrome was more thoroughly examined than other dongas. A line was taken from the high plain on the N.E. towards the hangar and a series of photographs taken and specimens col- 48 RAINFALL IN INCHES J F M A M J Jy A S O N D AV. MONTHLY RAINFALL 1929-30 1954 - 55 Figure 4.— Monthly rainfall for the years 1929-30 and 1954-55 and the average monthly rainfall. lected along the transect with side detours where variations were noticed. A long, very gradual slope with sparse vegetation and much bare ground led down from the plain of Figure 6 A already described. Bassia spp and Salsola kali, patchily distributed, were the main plants. Old rabbit burrows were numerous. Spreading from the mouths of some of these were big patches of Tetragonia erejuaea showing vivid green in contrast to the prevailing grey of the bassias. Further down the slope dried and cracked mud showed where water had been lying. An adjacent low level area had a re- latively rich cover of bushes up to 2 feet high of the perennial A triplex cryptocarpa with some plants of Lavatera, Nicotiana and Lycium. Her- baceous dicotyledons: the slender straggly climber Convolvulus erubescens, the legunie Psoralea cinerea and some composites and cruci- fers were scattered but principally in the shelter of the perennials throughout the lower levels of the donga. The central area (fig. 7A) was grass-covered with several big spreading clumps of Eremophila longifolia and a few small Pittosporum. The grass cover was of the tufted grasses Stipa nitida, Stipa sp. and Danthonia caespitosa. Towards the periphery of the grass and beyond were a number of Acacia oswaldii bushes. Wherever seen these had a broad squat compact silhouette easily distinguishable at a distance. Many of them were heavily infested with the mistletoe Amyema preissii\ all showed rabbit pruning. Several had old bushes of Atriplex rhagodioides growing up in their shelter (fig. 7B). No isolated plants of the Atriplex occurred, presumably be- cause only within the protection of the Acacia could they escape destruction by i-abbits. At 12 miles south of the rail a big donga (Da) had a rather richer vegetation. Grevillea nematophylla, not found in Di, occurred both as trees and shrubby re-growth. Acacia oswaldii was in much more vigorous condition than in the airport donga and seemed free of mistletoe. There were a few small shrubs of Eremophila maculata as well as the taller E. longifolia. Enchylaena tojnentosa was growing in the shelter of a Pittosporum and Grevillea and there were extensive colonies of Atriplex cryp- tocarpa. The herbaceous cover was of the same species as in the first donga but more luxuriant, the ground was moist to the touch and moss occurred under some of the bushes. A few plants of Clianthus formosus ( Sturt Pea) were found here. A small donga 4 miles south of the railway had many rabbit burrows. Zygophyllum spp were relatively abundant on the bare mud with dwarf composites and there was a dense colony of Atriplex cryptocarpa. About 15 miles to the north of Forrest and adjacent to the 14 mile tree belt another big donga (D^) was visited briefly and some koda- chromes taken and specimens collected. Large shrubs present were as in other dongas: Acacia oswaldii, A. tetragonophylla, Eremophila longi- folia, Pittosporu77i phylliraeoides, and a few old trees of Grevillea nematophylla, one with an eagle's nest. Near the centre of the donga a big spreading clump of Grevillea (Fig. 7D) with abundant new growth and silvery dissected leaves contrasted with the heavy dark brownish leaves of Acacia oswaldii and the yellowish weeping foliage of the Pittosporum. In the shelter of this and other big shrubs were dense growths of trailing herbaceous species as listed for other dongas. Most of the herbaceous species were well past their maximum flowering and in fruit but with enough flowers left on some plants to enable identification. Bassias were present more or less throughout the donga. Large flat areas were grass-covered with the previously found species of Stipa and Danthonia, also Eragrostis dielsii var pritzelii in a big patch covering a depression within the donga. Apart from the dongas with trees and shrubs there are extensive flat areas at slightly lower level than the high plain and where the soil is deeper without the exposed travertine. These are more or less bare in dry years but carry a luxuriant cover of gi’asses after heavy rains. One such stretch, shown in colour plate (fig. 9A) was crossed about 7 miles north of the air- 49 Figure 5. — A piece of fiat lichen-encrusted limestone from the sui'face of the plain. The conspicuous species is Buellia suhalbiila. port, extending continuously for about H miles with further broken patches. This grass com- munity was made up of the same two species of Stipa and one Danthonia as found in the dongas. No detailed examination of the area was made. Although the three grasses were found to- gether in most of the grassed ai’eas, there was a difference in their distribution. Stipa nitida appeared to be the most xerophytic as it was the only species where grass occurred as sparse tufts (fig. 6D) on the higher levels (fig. 7A). The unindentified Stipa with golden brown fruits. Stipa sp aff fusca was abundant in the deeper part of the dongas. The best growth of Dan- thonia was seen also at the lower levels and in the more favourable habitats near airport and line. An observation of interest was the seeds of Stipa and Danthojiia lined up in the pattern of cracked dried mud where water had lain. The long hygroscopically twisting awns are par- ticularly suited to driving the seeds, radicle end down, firmly into the cracks. Minor depressions. A variety of smaller irre- gularities and depressions, into which water may drain and soil is deeper, form locally favourable habitats. Figure 7D, a photograph of broken ground about 5 miles west of Forrest, shows the greater size and abundance of plants in small depressions. One depression seen just south of the railway had a stand of Atriplex hymenotheca in flower. Four species of Bassia were also collected here. Slightly further east, on this rather stony iregular south side, other depressions with annual saltbushes were found and two plants of Kochia georgei. A stand of Heterodendrum oleaejolium had been found in this area in 1930, the trees heavily infested with mistletoe and mostly in poor con- dition. In 1955 all except one were dead, two fallen and a few standing. There had been no regeneration. Tree belt. About 14 miles north of the air- port and covering 20-30 acres, is a belt of Myall i Acacia sowdenii), spreading trees 10-15 feet high. In 1955 the majority of these were dead or almost so (fig. 8A), This tree belt had been visited in 1930 when most trees were alive and looking healthy (fig. 8B) even though they had just recovei’ed from a particularly severe drought. No young trees were seen in either year. One old semi-fallen tree, which had been photographed in 1930, was found again still alive and not very different 25 years later. Several eagles' nests were present both in 1930 and 1955. Exocarpos aphyllus found in 1930 was not seen in 1955. A few perennial salt- bushes were growing close to trees. The ground cover was low and fairly sparse but with a variety of annual species (figs. 8A & C). Helipterum fioribundum, in full bloom, was conspicuous and extended well beyond the limits of the trees but the plants were mostly only a few inches tall. Cephalipterum drum- viondii was present in smaller numbers. Other small composites were Podolepis canescens, Helipterum tietkensii and H. tenellum. Zygo- phyllum iodocarpum and Z. ovatum were 50 I Figure 6.— A. A part of the plain to the east of donga 1 showing outcropping and fragmented limestop at the surface: absence of living bluebush and sparse cover of Bassias e^. B, Another part of the plain to the north where bluebush (Kocfiia sedifolia) was in healthy condition. C. A sUigle plant sinewing partial recovery after drought. D Stipa nitida, in a slightly depressed area. The tufted habit is well shown in the foreground Plants. 51 Figure 7.— The dongas. A. The grass covered area of donga D, with ETemophila longifolia (2 clumps) and a Pittosporum phylliraeoides in left distance. B. Acacia oswaldii with Atriplex rfiagodioides both pruned by rabbits. C. More luxuriant growth in minor depressions — broken ground five miles west of Forrest. Atriplex hymenotheca, centre, Atriplex cryptocarpa grasses and other plants. Typical stony plain in the background. D. A clump of Grevillea nematophylla in the northern donga Do. 52 Figure 8. — Tree belt and soak. A. General view of part of the 14 mile tree belt in 1955 showing most of the trees dead. B. View in 1930 shows the habit of the living Myall (Acacia sowdeiiii) and some dead trees. C. Detail of undergrowth in 1955, Helipterum flori'bundum, Zygovhy^ium. spp, grass. D. View of part of the soak in 1930; lush growth of Helipterum tietkensii in foreground, Lavatera etc. behind and the trees on right skyline. 53 abundant forming almost pure stands in places. Salsola kali was also abundant, as were the almost universal bassias. with scattered small tufts of Stipa nitida. A few small plants of Nicotiana goodspeedii were found. Concentra- tion of plants against fallen logs and dead plants, and in slight depressions was very noticeable. Tree belt soak. A particularly interesting area locally known as “the 14 mile soak” led into the tree belt, possibly marking an underground, or sunken, drainage system. A distinct edge was marked by a line of bushes — Kochia. Lyciurn, Lavatera — with, to the lower side, a lush growth, up to 24" tall (Colour plate fig. 9B) of the grass Eragrostis setifolia. and of Helipterum tietkensii — a tall slender scented composite with abundant small silky heads. Further over was an area of bare and broken ground with old rabbit burrows, part stony, part rather "fluffy’' soil, all extensively dis- turbed by rabbits and with a very patchy cover of the above mentioned grass and com- posite. sometimes mixed, more often in pure stands. Colour plate (fig. 9B) shows part of this soak. Figure 8B of the area in 1930 shows the rich- ness of the growth that year. Also in 1930 in a section of the depression further north was a luxuriant growth of Trigonella suavis- sima. which had not been seen anywhere else. This species was not found in 1955 but it is probable that that particular section of the depression was not reached. The plain outside the depression was the most barren seen anywhere, no living bluebush or salt bush and practically no herbaceous plants — mostly bare eroded soil between old dead stumps— no doubt denuded by the rabbits which inhabited the "soak”. Disturbed areas. In the neighbourhood of the airport, near the station and along the railway line inevitably the ground has been considerably disturbed, and some of this dis- turbance provides habitats more favourable than on most of the Plain. Loosened soil, de- pressions. drainage channels and, in places, ad- ditional water and nitrogen benefit both intro- duced and native species. For instance a drain along the airport fence had a lush growth of Danthonia. Atriplex hymenotheca, A. spongiosa, Salsola. Senecio and other indigenous com- posites, the introduced Sonchus and several species of introduced crucifers. On disturbed muddy areas where water had collected three species of Bassia. Atriplex spongiosa, A. hyvie- notheca. two species of Zygophyllum. Helip- terum floribundrun and Senecio lautus were common and in general more robust than in undisturbed areas. Introduced weeds were found only in the neighbourhood of line and airport. Some of these may have become naturalised but others are probably only of sporadic occurrence from seed dropped from trains, dependent on finding temporarily favourable niches and not long persistent. The difference in lists of introduced species from the two visits is in keeping with this suggestion. The native plants found on the two visits were essentially the same. Comparison between 1955 and 1930 Rainfall in each of these years was abnorm- ally high but the amount and distribution was very different as can be seen in Figure 3. 1955 was the second wet season after several dry years and the rain had been fairly evenly dis- tributed with the heaviest falls in October, 1954, and June, 1955. 1930 had the highest total rainfall ever recorded at Forrest and over six inches, eaual to the average annual total, fell in four days at the end of February, This occurred after the most severe drought recorded. Some of the differences in plant growth were undoubtedly related to these climatic differ- ences. As seen in August. 1930, only six months after flooding rains, the perennials. Eremopliila spp, Acacia spp. Kochia sedijolia and peren- nial species of Atriplex mostly had tufts of new foliage on old defoliated stems, many plants had not survived the drought. In October, 1955. most surviving perennials had abundant healthy foliage as the result of two successive favour- able years. On the other hand, the herbaceous vegetation was not nearly as dense and luxuriant in 1955 as it had been in 1930. This was particulai'ly noticeable with Helipterum fiorihunduvi which had in 1930 formed complete cover in places and where the individual plants had been much taller. There is no doubt that the ground cover as a whole had been denser and the plants taller in 1930 but as the rainfall for the first half of the year had been almost twice as much this is no basis for suspecting any long term change in the herbaceous vegetation. It is in- teresting that the same herbaceous species were collected at each visit and had flowered about the same time in spite of the differences in total amount and distribution of the rain. For the perennial cover both authors were satisfied that there had been a real deteriora- tion. In the Myall belt most of the trees had died. Figures 8 A and B show the difference although not taken from the same spot. Other 1955 photographs, too poor for publication, do include a tree recognisable as one photographed in 1930. No young trees had been seen in either year so it seems unlikely that the stand will recover. Regeneration from seed could have been expected in 1930 (16"' and 1942 (14"). It seems likely that it was prevented by rabbits and that they are also responsible for at least some of the deterioration of the Atriplex and Kochia. Rabbits spread over the plain after wet seasons and no doubt as drought develops and the annuals disappear the grazing pressure on the perennials must be intense, before the unfortunate animals succumb. The absence of living bluebush near the railway line and on the plain near the "soak", both areas with numerous rabbit burrow’s, would support this. With a perennial vegetation in precarious equilibrium with its environment where estab- lishment of seedlings is alw^ays difficult, rab- bits can destroy the seedlings before they are old enough to tolerate any grazing and so effectively prevent regeneration. 54 Figure 9.— Top. Grass community 7-8 miles north of Forrest. Bassia spp. in foreground. Bottom. Soak— Heiip£er7i?n tietkensii in the depression, a large Kochia sedifolia plant on the rim. Discussion The plant communities seen at Forrest are typical of the central and western side of the Nullarbor Plain. The same bluebush association of the higher levels in many parts in very de- nuded condition, the flats with grass after rain, and the dongas of varying size can be seen from the train along the 165 miles between Forrest and Rawlinna. The transition from the open dwarf shrub- land of the Plain to the woodlands with Mallee Eucalypts, Acacia or Casuarina and an under- growth of saltbush- bluebush or spinifex. occurs very gradually on the western side. The bound- ary of the Plain is usually put between Naretha and Rawlinna (fig. 1), but there is no clearly recognisable boundary for the vegetation: stands of shrubs and small trees become gradually more frequent from some miles east of Raw- linna, westward. Although the Nullarbor Plain is distinctive in appearance and recognised as a geographical entity the vegetation consists of impoverished extensions of types found in slightly higher rainfall regions to the north east. The Kochia- Atriplex communities of northern South Aus- tralia and western New South Wales are de- scribed as having spaces between the bushes more or less equal to the diameter of the plants; on the Plain the spaces are vastly greater. The occasional belts of Acacia sowdenii could be considered outliers of the more extensive Myall formations outside the limits of the Plain and species of the dongas are mostly found in the surrounding shrub or woodland communities. It seems probable that most of the perennial species are near the limit of their tolerance of low rainfall. The stress of the climate is shown in the number of plants dead after a prolonged drought and in the structure of the woody stems of shrubs. When plants recover after drought dead stems are left projecting, (fig. 60 and the cambium has often been killed on one side of surviving stems resulting in uneven and de- formed growth. With an average annual rainfall of only 6^ inches the Nullarbor Plain could be classed as desert and as with most desert areas perennial species are few and annuals form the greater percentage of the flora. Nevertheless the con- cept of tiny ephemerals appearing, flowering, fruiting and dying in a few weeks as known for some deserts does not seem to apply here, ex- cept for very few species. The grasses, bassias and annual saltbushes and at least some of the herbaceous composites and legumes, which form the bulk of the herbaceous vegetation, may last for many months and even more than a year under favourable conditions. The annual ever- lastings Helipierum floribundum and Cephalip- terum drummondii and also Goodenia pinnati- fida showed evidence of extended growth and in the 1955 specimens, of two distinct periods of growth and flowering. Local comment in October was that these and some legumes had been flowering for many weeks and photographs taken in early December showed evei*lastings still in flower. Stipa nitida is known to behave as a perennial under favourable conditions though more often as an annual in the drier parts of its range. Perhaps the ability to shorten or lengthen the life span is one of the effective adaptations to variable rainfall. The Chenopodiaceae, particularly Atriplex spp. have been shown to be particularly well adapted to the absorption of moisture through the leaves and it is probable that dew plays an important part in extending the effectiveness of light fails of rain. Heavy dews and occa- sional fogs are known on the Plain and more knowledge of their contribution to the survival of grasses and other species would be valuable. The place of dew in the survival of rabbits is suggested by the observation by local residents of rabbits lined up along the train line in early morning licking the dew from the rails. A three day visit to a region does not allow study of the ecology beyond recognition of species and types of communities, but it does suggest possibilities for investigations by some- one living in the area. Within the dongas there is great variation in the shrubs and ground cover associated with minor differences in habitat. McCrumb (unpublished teachers thesis) at Reid made some useful observations on depths of soil associated with plant communities and on growth habits of certain species. Some detailed observation on the percentage recovery of Kochia and Atriplex after drought and conditions necessary for their replacement by seedlings would be valuable. Is it true that there is at the present time a real deterioration of the bluebush and saltbush communities as the authors suggest, and. if so, how far are rabbits responsible? Some long term studies of regeneration of species of Acacia. Atriplex and Kochia. Heterodendruvi, Stipa which extend across the Nullarbor have been made in South Australia, particularly at Koonamore (Hall et al 1964; earlier papers are listed in this), but in regions much further east and in rather differ- ent habitats. There is need for ecological studies on the western side of the Plain. Flora Systematic representation. The number of Angiosperm taxa collected was 105 and their totals and relative numbers are given in Table I. Indigenous plants comprised the majority of the 27 families present. Among these 4 were prominent in both numbers of species and in- dividuals. The Poaceae (7 sp. and 1 ssp.), Asteraceae (14 sp.), Chenopodiaceae (19 sp.) and Fabaceae (7 sp. and 1 ssp.) together con- tained half the genera and over half the species. The remaining 19 families were each repre- sented by only 1 to 4 species. The vegetation was composed principally of large numbers of chenopods and grasses, with composites con- spicuous in smaller az’eas. Legumes were TABLE I. Tainilies Genera Sl)ecies Sub- Varieties species Total 27 07 98 4 Indigenous .. 24 48 78 3 ‘> Zntrodueed .. <) 20 20 0 2 55 usually found in the moister parts of the don- gas, where Lotus cruentus and Swainsona campestris were locally massed. Trigonella suavissivia formed an extensive and dense colony in one part of the soak. Introduced plants were mostly few in num- ber and not prominent among the luxuriant growth of saltbushes and grasses. Exceptions \vei‘e tall robust plans of the Brassicaceae. a single flowering colony of Asphodelus ^istulosus, large plants of the two varieties of Medicago polymorpha and the grasses Lophochloa puviila and Schismus harhatus. Only 4 of the 9 families were represented by more than one species. These were Poaceae i6 sp.>, Brassicaceae (5 sp.), Boraginaceae (2 sp.) and Asteraceae (3 sp.). Of the lower plants, 12 lichens and 1 moss (sterile and not identified) were found. No ferns were seen. Geographical distribution. The range of a number of indigenous species cannot be deter- mined until more field studies are made on the Plain and its surrounding areas. On present evidence the Plain is the centre of distribution for only 3 species — Atriplex cryp~ tocarpa, Swainsona campestris and Calotis breviradiata. Most of the others have a wide distribution, 67 out of 76 occurring both on its western and eastern sides throughout the more arid parts of Western Australia and South Australia. Some of them, such as Pittosporum phylliraeoides^ Salsola kali. Enchylaena tomen- tosa and Senecio lautus are found in both coas- tal and Eremean areas. To the east, 56 extend into western New South Wales and 48 are recorded from Central Australia. A few- species have a still wider range and are found in the higher rainfall areas of south-western and south-eastern Aus- tralia. These are Danthonia caespitosa, Oxalis corniculata. Euphorbia drumviondii, Lavatera plebeia, Convolvulus erubesceiis, Plantago varia and Vittadinia triloba. The distribution of Bassia parallelicuspis and Erodium cygnorum ssp. glandztlosurn is con- sidered to be eastern, while that of Erodium cygnoru7n ssp. cygnorum is mainly western, though it has been recorded from northern South Australia (Carolin 1958). The present known range of Eragrostis dielsii var. pritzelii, Grevillea nematophylla an undescribed var. and Atriplex hymenotheca is western. All three have been recorded from widely separated localities, so their range may be found to extend further east when more in- formation is available. All the introduced species had previously been recorded for Western Australia and South Aus- tralia. Twelve were collected in 1930 and fif- teen in 1955. Ten of the latter were new re- cords for Forrest (see in Annotated List). Uordeum leporinum, Lophochloa pumila, Schismus barbatus, Chenopodium murale, Papaver hybridum, Brassica sp. and Medicago polymorpha var. brevispina, collected in 1930, were not found in 1955. Annotated List of Species from Forrest Specimens, after detailed examination, were compared with those available in the Tate Herbarium, Adelaide, the State Herbarium of South Australia, the Western Australian Her- barium, and a few in the National Herbarium of Victoria. Several specimens were not deter- mined. For some others, where resemblances to particular species were found to be close, dif- ferences have been noted and the species de- terminations given are regarded as tentative. Nomenclature followed is that in Black's Flora of South Australia (2nd ed. 1943-1957) and its Supplement (Eichler, 1965). Collections are in the herbarium of the Botany Department, University of Western Australia (U.W.A.), and a duplicate set has been sent to the C.S.I.R.O. Herbarium, Canberra. Localities are shown as under. Distances are approximate from the Forrest railway station. P — plain TB — tree belt, N 14 miles S — soak. N 14 miles R — disturbed soil near railway line and air- port D — dongas D, — NE 1 mile T> 2 — N 15 miles Dr, — S 12 miles D. 1 — S 5 miles The months August and October refer to plants collected in August 1930 and October 1955 respectively. A species was abundant and in ftower and fruit unless otherwise stated. An asterisk denotes an introduced species. ANGIOSPERMAE POACEAE ( GRAMINE AE ) *Aue7ia fatua L. (R) — in fruit (Oct.). *Bromus unioloides H.B.K. (R> — near septic tank overflow, rare (Oct.). Danthonia caespitosa Gaudich. (P Di D 2 S R) — often mixed wdth Stipa; variable in height =t 30 cm. in moist places, small scattered tufts ± 10 cm. on bare areas. (Aug. Oct.) Eragrostis setifolia Nees (S) — mixed with Helipterum tietkensii to form a dense mass; ± 30 cm. tall; smaller and less numerous in 1955 (Aug. Oct.). Eragrostis dielsii Pilger (P S R) — small erect tufts in damp depressions (Aug. Oct.). Eragrostis dielsii var. pritzelii Pilger (P D 2 R) — mat plant, on bare clay around aerodrome and on surface of donga among erect plants of a fairly dense ground flora. (Aug. Oct.) This variety described by Pilger (1904) has since been recorded from some widely separated localities in Western Australia 'Gai'dner 1952). The habit of the Forrest specimens W'as com- pact with numerous horizontally spreading culms without erect ones and they appeared distinct from the erect tufted plants of 56 E. dielsii which occurred near them by the aero- drome. Both erect and mat plants matched those of E. dielsii and its var. pritzelii in the W.A. Herbarium, *Hordeu77i leporinum Link (R) — rare (Aug,). *LcMum pereniie L. (R) — rare (Oct.). *Lophochloa pumila (Desf.) Bor. (R) — (Aug.). ""Schisinus harhatus (L.) Thell.. . The closest resemblance of these plants seems to be the South African species. A. s^iberecta Verdoorn. Atriplex sp. (No. 83, 1930) (R) — prostrate, woody, stems ± 15 cm; leaves small. 5-9 mm long, obovate, green above mealy below; monoe- cious; axillary clusters of very young male and female flowers, bracteoles shortly stalked. 3- toothed, the middle tooth longer and deltoid: no fruits developed (Aug.). The flowers and bracteoles of this specimen are similar to those of the preceding ones but it differs in habit and foliage. Bassia obliquictLspis Anderson (P Di> — on shallow limestone soil, also deeper soil in donga, with Atriplex hymenotheca and other Bassia spp.; plants small, compact, branching, 6-8 cm tall (Aug. Oct.). Bassia parallelicuspis Anderson (Pi — rare ex- cept in one small area south of the line; plants soft, erect, branching. 6-20 cm tall; tomentum brownish: flowers and young fruits (Aug.). Bassia patenticuspis Anderson (P Dt D.i TB R( — colonizers; plants small, tomentum grey; fruits with 2 spines up to 6 mm long, acicular, glabrous except near base, some reddish distally (Aug. Oct.). Equal spines were rare and in a number of cases one spine was reduced to a tubercle. Variations in length occurred on a single plant. Ising (1964) says that more than half the specimens showing this type of varia- tion in spine length have come from the Nullar- bor Plain. Bassia sclerolaenoides (P. Muell.).

— shrubs, isolated or in groups in dongas or smaller depressions on plain; 2-3 m tall; dehisced fruits and few buds (Aug.), buds, flowers and mature fruits (Oct.). In 1930 fruits (red) of one of the Loranthaceae were germinating on some of these shrubs and in 1955 those in a donga (Di) were heavily parasitized by Amyema preissix. Acacia soxvdenii Maiden (TB) — trees scat- tered over 20-30 acres; 5-6 m tall; flowers in globular heads (Aug.) Flowers and young fruits on some with sparse foliage, others ap- peared dead in 1955 (Oct.). 58 Acacia tetragonophylla F. Muell. (P Di D 2 ) scattered shrubs: 1-2 m tall; flowers, no fruits (Aug.), few flowers numerous fruits (Oct.). FABACEAE (“ PAPILIONACEAE) Clianthus jormosus iG. Don) Ford et Vick- ery (Da S) — plants large, in flower (Aug.). Rare and small, only in one donga (Oct.). Lotus cruentus Court (Di Da) — in shelter of other plants: stems long, trailing (Oct.). *Medicago polyviorpha var. brevispina (Benth.) Heyn (R) — occasional; plants large; spines on pod short (1 mm) both straight and hooked (AugJ. *Medicago polyniorpJia var. vulgaris (Benth.) Shinners . In 1955 (Oct.) most trees were dead. MALVACEAE Lavatera plebeia Sims (P Di TB S R) — fre- quent; scattered shrubs up to 1 m tall (Aug. Oct.) . Sida cardiophylla F. Muell. (R) — rare, small shrub, low spreading; in bud (Aug.). CONVOLVULACEAE Convolvulus erubescens Sims (,P Di R) — occa- sional in depressions on plain, abundant at low- er levels of donga; mat plants, large, stems slender, trailing and twining up to 60 cm long (Aug. Oct.). Convclvuhis sp. (Dj) — a large bright green prostrate plant (Oct.). Differed from C. erubescens in its longer fruits and two sepals enlarged and spreading. BORAGINACEAE *BuglGssoides arveiise (Patersons Curse) (L.) Johnston (R) — rare (Aug. Oct.). Some plants were erect, up to 30 cm tall, with flat sessile leaves, obtuse, ± 4 cm long by 6 mm wide. Others were moi’e spreading, branching mainly near the base of the stem, with shorter, nar- rower, lanceolate or oblong leaves, 1.5 cm long by 2-3 mm wide. ^'Echiuvi lycopsis L. iR) — rare (Oct.). Omphalolappula concava (F. Muell.) Brand (R) — rare (Aug.). SOLANACEAE Lycium australe F. Muell. (P Di S) — occa- sional: no flowers or fruits in 1930, both present in 1955. Nicotiana goodspeedii Wheeler (Di TB R) — frequent; small in ground flora, 15-40 cm tall in centre of donga, glabrous: flowers cream to pale yellow lOct.). Nicotiana suaveolens Lehm. (R) — among weeds near a septic tank Overflow; a single robust, glabrous plant (Oct.), Nicotiana sp (possibly N. benthamiana Domin) (TB) — this specimen was lost after the following notes were made. 59 Plants numerous at the edge of a depression near Acacia sowdenii; up to 1 m tall, most about 50 cm; glabrous, basal leaves very large, cordate blades up to 20 cm long narrowing into long petioles, cauline leaves ± 10 cm not decurrent ; flowers yellow, calyx lobes acute, divided nearly halfway to the base, hinsute, corolla tube ± 20 mm, 2-3 times as long as the calyx, lobes short, obtuse, stamens 5, 4 attached higher on the tube than the 5th; capsule smooth, as long as the calyx, seeds pitted (Aug.). MYOPORACEAE Eremovhila latrobei P. Muell. re pub- lished by West Australian Newspapers Ltd. The final one. in handsome format, Wildflowers of Western Australia, appeared in 1959. In 1937 Gardner was stationed at the Royal Botanic Gardens, Kew. as the first Australian botanical liaison officer. Between 1924 and 1962 he delivered courses of lectures on plant geography and systematic botany in the Faculty of Agriculture of the University of Western Australia. He served as a member of the State Gardens Board (later National Parks Board), and, in later years after retirement, as honor- ary consulting botanist to the King’s Park Board. As a conservationist his achievements were notable and he was instrumental in pursuad- ing the Government to proclaim the following five extensive flora reserves; (1) at the lower Murchison River; (2) the Hill River Reserve (Mt. Lesueur); (3) the reserve south of Southern Cross (Lake Cronin); (4) the ai'ea be- tween the Gairdner River and the Hamersley River (including the Barren Ranges); and (5) the area between Cape Arid and Israelite Bay. A list of his writings, covering some 320 items between 1923 and 1962, is filed at the Depart- ment of Agriculture, the Battye Library in the State Library, the Botany Department of the University, and at the Royal Botanic Gardens. Melbourne. 63 INSTRUCTIONS TO AUTHORS Contributions to this Journal should be sent to The Honorary Secretary, Royal Society of Western Australia, Western Australian Museum, Perth. Papers are received only from, or by communication through, Members of the Society. The Council decides whether any contribution will be accepted for publication. All papers accepted must be read either in full or in abstract or be tabled at an ordinary meeting before publication. Papers should be accompanied by a table of contents, on a separate sheet, showing clearly the status of ail headings; this will not necessarily be published. 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Further reprints may be ordered at cost, provided that orders are submitted with the returned galley proofs. Authors are solely responsible for the accuracy of all information in their papers, and for any opinion they express. Journal of the Royal Society of Western Australia Volume 53 1970 Part 2 Contents 4. — A new penc’-unculate barnacle, Paralepas georgai sp.nov. (Crustacea: Cirripedia — Thor- acica) epizoic on Australian spiny lobsters and crabs. By A. Daniel. 5. — Alpha-activity of Western Australian Soils and wheats. By J. H. Chute, R. A. Clapp and J. P. Quirk. 6. — Notes on the Flora and Vegetation of the Nullabor Plain at Forrest, W.A. By E. R. L. Johnson and A. M. Baird. Obituary. — C. A. Gardner; M.B.E. Editor: A. S. George Assistant Editor: W. A. Loneragan The Royal Society of Western Australia, Western Australian Museum, Perth 68781-4/70-570-t ALEX. B. DAVIES, Government Piinter, Perth, Western Australia