CRASSULA, Linn., sect. TLLLAEOIDEAE, Schonl. 
43 
of species occur in South Africa, but there are also a number in Australia, 
New Zealand and Tasmania; South America (especially Chile and Peru) 
has again a large number of species. From South Africa they extend 
through the mountainous parts of tropical Africa to Socotra, the Medi- 
terranean region, the western part of the continent of Europe, and the 
Canary Islands. One species is found in the Himalayas. In America 
they extend through Mexico to the United States. I hope to be able to 
give a more detailed account of the distribution shortly, when I shall deal 
with the species found outside temperate South Africa. 
A sharp definition of the sect. Tillaeoideae is impossible. They consist 
of small, mostly annual plants adapted in the majority of cases to damp 
conditions (some are real water plants) while some are distinct Xerophytes 1 . 
The flowers are rarely placed in complicated inflorescences, the petals are 
stellate, rarely suberect, but never form a decidedly urceolate corolla (though 
an indication towards it is found, e.g. in Cr. expansa, .). Moreover the 
subapical mucro so often (though not universally) found in the species 
belonging to Eu-Crassula is practically always absent. I have only found 
an indication of it in Cr. expansa , Ait. (Cr. filicaulis, Haw.). As a matter 
of fact no sharp line can be drawn between the Tillaeoideae and other 
sections of Crassula. Cr. expansa, A*t- leads up to Cr. acutifolia, Lam. and 
allied species. Various species lead up to Cr. centauroides, L. and allied species. 
These species again cannot be sharply separated from the sect. Petiolares 
and these again lead to the sect. Latifoliae. There are even relations with 
Harvey’s section Crenato-lobatae and with the subgenus Pyramidella, as will 
be noted later on. It looks almost as if these small-flowered species had 
formed the original stock from which the other Crassulas more or less 
directly originated. I have grouped the species known to me around a 
number of species fairly well known. Perhaps later on it will be possible 
to give a key ‘to all of them. 
Before concluding these preliminary remarks I wish to say a few words on 
the nectar-scales. These delicate structures (sometimes not much more than 
1/10 mm. long) are often very difficult to detect after the material has once 
been dried. However, whenever I have had sufficient material at my 
disposal I have always been able to find them in any plant belonging to 
this section, except in specimens of Cr. muscosa (L.) Roth. (Bulliarda 
muscosa, DC.) and in Cr. bonariensis, Cambess. ( Tillaea purpurata, Hook. 1. ). 
Other observers have also failed to detect them in these plants, which 1 eally 
seem to lack them. In South African species they appear to be always 
present. The nectar-scales (squamae) are generally very characteristic in 
shape and size, but, owing to the difficulties of dissecting, one cannot always 
1 We find the same combination of waterplants and distinct Xerophytes also in tin 
Hypoxis (in the older sense) and in other genera, or at all events in closely allied ytm i i 
