200 Gibbs . — Bio-histological notes on some new 
In considering the morphological value of the scale-leaves of the corm of 
Hesperantha in comparison with other members of the order, there is very 
little literature to fall back upon. Irmisch 1 found that the corms of Crocus , 
Gladiolus , and Romulea are the product of the preceding year s activity of 
the plant and belong to an axis of a next lower order. As these dry up the 
basal internodes of the flowering axis thicken into fresh corms, which give 
up their reserve storage material to a new generation (Spross-Generation) 
next year. This year’s corm has usually three scale- leaves, which are 
inserted on the base of the corm, but buds arise in the axils of the scale- 
leaves. In an earlier paper Irmisch 2 , in considering Crocus , finds no transi- 
tion between the scale- and the foliage-leaves, a short internode separating 
the uppermost scale-leaf and the lowest foliage-leaf. Both forms of leaf 
die off later, but the bases of the former remain as a protective investment 
to the corm, which in a moist climate is thrown off every year. As the 
thickened portion of the stem in these cases consists of several internodes, 
no doubt the number of these latter determines the number of the scale- 
leaves. In Hesperantha , Geissorhiza , and Lapeyrousia therefore only one 
internode of the stem can be involved in the formation of the corm and we 
get one corresponding scale-leaf inserted on the base of the latter, the next 
season’s corms arising in the axil of that leaf. In this case the scale-leaf does 
not rot away, but lignifies, remaining as a permanent investment or tunic. 
In this peculiarity we find an interesting parallel amongst the grasses. 
Hackel 3 , in a paper on some peculiarities shown by the grasses of dry 
climates, enumerates so-called £ Tunika-Graser 5 as showing protective 
scale-leaf investment according to their habitat. The grasses of the fertile 
meadows of Northern Europe and North Asia are characterized by delicate 
scale-leaves which soon decay, and only the remains of one or two are to 
be found in the base of the culm. In grasses from dry climates, on 
the contrary, these scale-leaves thicken and persist, and, according to the 
type of persistent thickening, may be divided into £ Stroh-Tuniken 5 and 
£ Faser-Tuniken ’. The former develop into hard, often smooth, entire 
straw-like scales, while in the latter the soft parenchyma breaks down, 
leaving the bundles isolated. This type may be carried further in the 
‘ Fasernetz-Tuniken ’ in which the bundles anastomose again, forming 
horizontal as well as longitudinal threads, and both these types of tunic 
investment, persisting, result in many layers over the base of the culms, 
protecting the young shoots. These tunics also serve to collect water, as 
the superposed layers hold it tenaciously. Having had occasion recently 
to look through the Tropical and South African genera of the Liliaceae, 
Irideae, and Amaryllideae, it was very striking to see that what Hackel 
1 Irmisch, Morpholog. Beobachtungen (Berlin, 1855, pp. 10-25). 
2 Irmisch, Zur Morphologie der Knollen- u. Zwiebel-Gewachse (Berlin, 1850, pp. 89-94 
and 166-70). 3 Hackel, 1 . c. 
