The following is for entertainment purposes only
DMT is a prohibited drug in australia and most other countries.
5MeODMT is probably still legal in most australian states, but
is prohibited in many countries.
I take no responsibility for the accuracy of the following. It
could all be lies I invented to get you to kill yourself.
There are several species of plant that contain interesting 
tryptamine alkaloids that grow in australia (either introduced
or native). They include :

Phalaris aquatica (nee tuberosa)  "Toowomba canarygrass"
Phalaris arundinacea "Reed canarygrass"
Arundo donax "Giant river reed"
Desmodium gangeticum
Desmodium pulchellum
Acacia maidenii "Maidens wattle"
Acacia phelbophylla "Buffalo Swallow Wattle"

A.phelobophylla's leaves contain .3% per wet mass DMT, with few
other alkaloids (6). Grows naturally only in Victoria (around
Mount Buffalo).

A.Maidenii's bark contains .3% per mass N-methyltryptamine and 
DMT in a 2:3 ratio. Extraction is difficult but far from 
impossible by normal (acid/base, partitioned solvents) methods
(6). Grows naturally in NSW,Vic.

D.pulchellum's green parts contain 5MeODMT, with few other (active) 
alkaloids. (1)

D.gangeticum contains indole alkaloids in its green parts. 1kg 
wet mass of plant material yielded 2.5g total alkaloids as 
follows :
DMT              : 0.41g
DMT     Nb oxide : 0.33g
5MeoDMT          : 0.57g
5MeODMT Nb oxide : 0.18g
Tetrahydroharman : 0.03g
6-methoxy,2-methyl B carboline : 0.21g
Grows mainly in SE asia and northern australia.. (2)

A.donax leaves, flowers and rhizomes contain DMT and 5MeODMT, 
but unfortunately also contain about 3 times as much gramine
(3(aminomethyl)indole) as DMT and 5MeODMT combined. This renders
extraction of DMT very difficult (basically only possible by
chromotography) (3). Widely distributed along temperate 
waterways all through Australia. Common in Perth.

P. arundinacea contain DMT,5MeODMT and other B-carboline and
3-(n-aminoalkyl)indoles along with gramine. This grass is 
interesting in that different strains contain widely varying 
total and relative concentrations of alkaloids. In a study in 
Australia (4) only 5 out of 12 strains tested had significant
amounts of 5MeODMT or DMT in them, with the rest contain mainly
gramine, hordenine, or tricyclic indole. While this plant is
widely recommeded for extraction of DMT, these results make
me suspicious of the validity of this recommendation. 
One possible reason for success with this plant is the fact that
those specimins containing gramine and hordenine are less 
palitable to stock than those containing DMT or other 
tryptamines.
This plant is a major pasture grass in the southern half of 
Australia and has become naturalised in some areas of western 
australia (and possibly elsewhere). Seeds are available through
standard agricultural sources.

P. aquatica contain DMT, 5MeODMT and bufotenine, along with
up to 5% B-carboline tricyclics. Alkaloid concentrations and
relative levels vary with growth condition and strain, as is
extensively documented (5). For maximum DMT content, the
grass needs to be grown in shady (15-28% of full sunlight), warm
(16-21C diurnal range) conditions with high soil nitrate 
level. Long days are also conducive to faster alkaloid 
production (as a byproduct of faster growth).
Under good conditions, alkaloids may make up 180mg per 100g of
dry plant mass. Each plant weighs about 1.8g (dry) after 4 weeks 
growth, making for about 500 plants to the gram of alkaloids 
extracted.
Alkaloid conc. also varies with stain, but any of the normal 
commercial strains (ie _not_ "Low alkaloid" varieties) contain
good DMT content and good ratio of DMT/5MeODMT to bufotenine and
other indoles.
P. aquatica is another major pasture grass in the southern 
half of australia, and has become quite widely naturalised. Seeds
are again easily available.
This would be my plant of choice for obtaining DMT in WA.



References :
1: J. Org. Chem vol 31 p 2284.
2: Banerjee P.K. and Goshal S., Aust J. Chem vol 22 p 275
3: Dutta S.K and Goshal S., Chem. and Ind. Dec 1967 p 2046
4: Gander J.E et al, Phytochem. vol 15 p 737
5: Moore R.M et al, Aust. J. Biol. Sci. v 20 p1131
6: Australian highs FAQ and references therein.
7: Smith, T, Phytochem vol 16 p 171 and references therein
8: Australian Grasses : A field guide. (author unknown)
9: A Key to Australian Grasses, B.K.Simon, Queensland Herbarium.
10: The Vegitation of the Perth Region. (author unknown)