Tlie Growth-Forms of Natal Plants. 
627 
appears on the trees. Being, for the most part, deeply rooted, they occupy 
a different stratum of the soil from the grasses. 
G-eophytes, according to Eaunkiaer's " normal spectrum," only form 3 per 
cent, of the world's flora as a whole. In Natal the proportion is about 18 per 
cent., or six times the normal, so that this must be considered quite a charac- 
teristic South African type. Their great abundance depends partly on the 
same conditions as we have seen have led to an increase in the number of 
Chamaephytes and Hemicryptophytes — the need for protection against 
drought, etc., in winter — partly on the further need for producing seed 
early in spring, before the Chamaephytes and Hemicryptophytes (grasses) 
grow tall enough to shade them. 
The G-eophytes share their habitat with the Hemicryptophytes, both 
being mostly veld plants. The H. class is below the normal, according to 
Eaunkiaer's normal spectum. The percentage is 18 instead of 27 (see 
table on p. 632). But if we combine the two classes, which we are justified 
in doing, seeing that they are alike in so many respects, we get for Natal 
18 + 18, or 36 per cent, of H. and Gr ; for the world, as a whole, 27 + 3, or 
30 per cent, of H. and G. The increase in the number of Geophytes in 
Natal may, therefore, be considered to have taken place at the expense 
of the Hemicryptophytes. When we take the two together, we get a higher 
percentage than the normal (36 per cent, as against 30 per cent.). 
The total number of Geophytes is cir. 550, including 120 Asclepiadaceae, 
135 Orchidaceae, 49 Irideae, 58 Amaryllidaceae, 150 Liliaceae, all except 
38, therefore, belonging to these five families. 
In the Asclepiadaceae we get either a tulDerous " rootstock," which in 
some species {e.g. RapJiionacme) is very large, or a cluster of tuberous roots. 
Many of the climbing species included in the lists of Phanerophytes also 
have tubers. The family, as a whole, has a milky latex. 
In the Orchidaceae the species included in the above list are the terrestrial 
orchids, with tubers usually ovoid or globose, sometimes lobed. The bulk of 
the Natal orchids are terrestrial (for the Epiphytes vide p. 631). 
In the Irideae we usually get a corm, as in species of Moraea, Tritonia, 
Watsonia, Gladio/us, Homeria miniata, etc., but sometimes a short, creeping 
rhizome, e.g. in Moraea iridioides. 
A number of Irideae have no tuberous underground organs, and are 
included among Hemicryptophytes. 
In the Amaryllidaceae we get a corm in Hypoxis spp., and Ciircnligo ; a 
bulb in the others. 
In the Liliaceae the rootstock is tuberous in Eriosjjermum and Tulhagia ; 
rootstock obscure in Anthericum ; rootstock small, roots wiry or fleshy in 
Ghlorophytum ; and in the other genera we get a tunicated bulb, which is the 
favourite storage organ in this family. 
The Aroideae (Richardia) have thick, fleshy rhizomes. 
