CHAP, ii GROWTH-FORMS n 



plants : for instance, species of Philodendron, ferns, and others. The 

 leaves are often short-stalked, more or less orbicular, and distichous 

 (so that the species often bears such names as ' nummulariaefolia ' and 

 ' serpyllifolia ') ; this constitutes the Jungermannia-form. 



(d) Land-plants with long erect long-lived shoots. To this sub- 

 class belong very many species that possess more or less woody stems, 

 or, less frequently, herbaceous stems. Among them are the following : 



Cushion-plants. Shoot-system richly ramified, often with the branches 

 densely packed to form hemispherical cushions. Foliage-leaves usually 

 small, more or less evergreen, remaining attached for a long time in a 

 faded condition, and decaying slowly. Buds open. Adaptation to a 

 cold, physiologically dry climate, or to cold dry air and a hot soil : dicoty- 

 lous plants such as Azorella, Raoulia, Silene acaulis, species of Saxifraga, 

 Draba, Dionysia, Aretia. Mosses assume similar cushion-shapes. 



Undershrubs (Suffrutices). There are a great many kinds of these 

 which are transition-forms between herbs and shrubs, and have incom- 

 pletely lignified stems, or lignified stems that soon perish. The yearling 

 shoot often is branched. The buds are often naked. They include 

 various types : 



Labiate type. Considerable parts of the flowering shoots die after 

 blossoming. Many are Mediterranean plants, adapted to a mild winter 

 during which rain falls, and are particularly found in Continental steppes 

 and maquis: species of Salvia, Lavandula, Thymus, Helianthemum, 

 Artemisia, Ruta. 



Acanthaceous type. Erect, weakly lignified, tropical forest-plants, 

 with thin leaves : species of Acanthaceae, Rubiaceae, Verbenaceae, 

 Piperaceae. 



Rhizomatous undershrubs having subterranean runners : Vaccinium 

 Myrtillus and V. Vitis-Idaea. 



Cane-under shrubs, 1 with lignified but commonly monocarpic shoots : 

 Rubus Idaeus, other species of Rubus. 

 Then there are also 



Soft-stemmed plants. Stems thick, green, soft, scarcely lignified ; 

 leaves usually very large. Plants essentially belonging to tropical forest 

 and marsh, and epiphytes : Araceae specially. 



Succulent-stemmed plants : Cactus-form. Stem lignified, green, juicy, 

 unbranched or feebly branched, often thorny. Foliage-leaves suppressed. 

 Buds sunken, often protected by hairs. Adaptation to a hot climate, 

 with prolonged drought. On deserts and rocks, usually forming very 

 open associations. Varying in size from trees to prostrate forms : Cacta- 

 ceae, species of Euphorbia, Stapelia. 



Woody plants with long-lived, lignified stems. Buds naked or scaly. 

 Evergreen or deciduous. To these belong 



Canopy-trees. 2 Dicotylous and gymnospermous trees, with well- 

 branched crown and many small leaves. The crown increases in size 

 from year to year, and the stem necessarily exhibits corresponding 

 secondary increase in thickness. Buds scaly, or at any rate not typically 

 open. Leaves, deciduous or evergreen ; extremely varied in form, 

 venation, and structure ; large, broad, and thin, simple or compound ; or 

 small, broad and coriaceous (sclerophyllous trees) ; pinoid (Coniferae) ; 



1 Drude's (1896) Schosslingsstraucher. 2 Drude's (i8g6)-Wipfelbdume. 



