Gilliesieae

Gilliesieae is a tribe of herbaceous geophyte plants belonging to the subfamily Allioideae of the Amaryllis family (Amaryllidaceae). Described in 1826, it contains fifteen genera and about eighty species. It has been variously treated as a subfamily or tribe. It is native to the Southern United States, Central and South America, predominantly Chile. Of the three tribes of genera that make up the subfamily Allioideae, Gilliesieae is the largest and most variable. The tribe was divided into two tribes in 2014, Gilliesiae s.s. and Leucocoryneae, based on differences in floral symmetry and septal nectaries. Gilliesieae are perennial herbaceous geophytes characterised by simple or prolific bulbs, sometimes with lateral rhizomes. Leaf sheaths long, tepals more or less fused and corona absent. Spathe formed from 1–2 bracts. Style more or less gynobasic. Ovary usually has two ovules per locule, side by side. There are 2–3 stamens. The commonest chromosome number is x=4. Gilliesiae is distinguished from Leucocoryneae by zygomorphic floral symmetry and the absence of septal nectaries. By contrast Leucocoryneae are zygomorphic and have septal nectaries. Leucocoryneae are terrestrial perennial herbaceous plants. They have tunicate bulbs, which may be simple or prolific (with bulbils), rarely lateral rhizomes. The outer bulb scales (cataphyll) are papyraceous, colourless or violaceous (Zoellnerallium). They may or may not have a garlic like odour. The leaves are large, with membranous sheaths, usually forming an underground neck. The leaf lamina is flat, green, and glaucous, glabrous or papillose. The inflorescence may be pauciflor (Ipheion, Beauverdia, rarely Tristagma) or pluriflor (up to 30). The spathe is formed by a single bifid membranous bract (Ipheion) or from two papyraceous bracts partially fused at the base. The pedicels, which are not articulated at the receptacles, are papilose or glabrous. The flowers are hermaphroditic and actinomorphic, the perianth corolla like, with 6 (8 in Beauverdia) tepals fused at their base to form a floral tube arising around the ovary. There are 6 stamens (8 in Beauverdia), 3 fertile and 3 not (staminodes), rarely 6 (Leucocoryne), in two whorls of three (Tristagma, Ipheion) or one whorl. The filaments which are adnate (fused) to the tepals, uniting at their bases, the anthers dorsifixed (attached at their back) are oblong, yellow brown or green. The ovaries are superior and sessile with three (four in Beauverdia) carpels and locules (four in Beauverdia) and septal nectaries. The number of ovules is either 2, 4 or 30 per locule, arranged in two rows. The style is apical and persistent. The stigma has three (four in Beauverdia) lobes, or is trifid, and is papillose. The capsule, which is humifuse (Ipheion, Beauverdia) or aerocarpic, globose or prismatic, and contains many seeds (pluriseeded) which are irregular and polyhedral with a black tegmen. The embryo is linear or slightly curved. Lindley described Gilliesia in 1826, after fellow botanist John Gillies, placing this genus and another Chilean genus Miersia which he described at the same time, in a new taxon, Gilliesieae. These and related genera have been variously assigned to families Liliaceae, Amaryllidaceae, Alliaceae and even Gilliesiaceae over their history, often as tribe Gilliesieae Lindl. In 1985, Dahlgren's treatment of the Alliaceae (now Allioideae) within the monocotyledons, recognised three subfamilies. Gilliesioideae (Lindl.) Am., together with Agapanthoideae and Allioideae. These corresponded to Hutchinson's (1959) three tribes within his expanded Amaryllidaceae (Agapantheae, Allieae, and Gilesieae). The Gilliesioideae contained nine genera endemic to the southern part of South America, predominantly Chile. In 1996, a molecular phylogenetic study of the rbcL gene showed Gilliesia and related genera clustering in a separate clade at subfamilial level. The authors rejected the proposal of Traub (1982) of a separate family, Gilliesiaceae (later resurrected by Ravenna), but rather created the Gilliesioideae, as one of three subfamilies within Alliaceae, together with Allioideae and Tulbaghioideae. As phylogenetically constructed, Gilliesioideae (Gilliesioideae (Lindl.) Am., Botany: 134. 1832 - Gilliesieae Lindl. in Bot. Reg.: ad t. 992. 1826. - Type: Gilliesia Lindl.) consisted of those New World Alliaceae not included in the other two subfamilies, which included both the former Gilliesieae (Ancrumia, Erinna, Gethyum, Gilliesia, Miersia, Solaria and Trichlora) together with Ipheion, Leucocoryne, Nothoscordum, and Tristagma. Garaventia and Steinmannia were not included in the study, but considered to be part of this newly reconstructed subfamily, a total of 13 genera. This is the circumscription which the Angiosperm Phylogeny Group (APG) accepted in the APG classification of 1998 and which later became known as Alliaceae sensu stricto (s.s.). In the 2003 update (APGII) it was proposed to include Agapanthaceae and Amaryllidaceae under Alliaceae, while recognising an argument for renaming the overarching family from Alliaceae to Amaryllidaceae. This construction of Gilliesioideae, which represented nearly all the Alliaceae genera (i.e. except Allium and Tulbaghia), implicitly recognised that it was composed of two groups or tribes, informally referred to as Ipheieae and Gilliesieae. The Ipheieae were actinomorphic, and included Ipheion, Nothoscordum, Leucocoryne s.l. (including Pabellonia and Stemmatium). Gilliesieae were rare, mostly zygomorphic, mostly endemic to Chile and typified by Gilliesa. It contained about eight genera (Ancrumia, Gethyum, Gilliesia, Miersia, Schickendantziella, Solaria and Trichlora). The genera of Gilliesioideae were thus morphologically and genetically diverse, which has made generic delimitation problematic and many species have at times been included in various different genera, and a number of genera have been shown to be polyphyletic. Consequently, the number of genera included tends to be variable A more detailed analysis using multiple markers (Fay et al. 2006) confirmed the monophyly of Gilliesioideae as a whole, as were the two tribes, although some genera such as Ipheion and Nothoscordum were biphyletic. In general the Gilliesieae, with their unusual floral morphology, have genera that are closely related. For instance Ancrumia, Gethyum and Solaria have been treated as three, two or one (Solaria) genus by different authors. (see Genera and notes) In 2009, Chase et al. more formally brought together the three families, Agapanthaceae, Alliaceae, Amaryllidaceae, under the single Asparagalean monophyletic family, now renamed Amaryllidaceae from Alliaceae, reversing the Dahlgrenian process of family splitting. This necessitated reducing the existing ranks of the component subfamilial taxa. This formed the basis for the 2009 APG classification (APGIII). Thus subfamily Gilliesioideae became tribe Gilliesieae (Baker, J. Linn. Soc., Bot. 14: 509. 24 Apr1875) within subfamily Allioideae of family Amaryllidaceae. Within the tribe they included thirteen genera including Leucocoryne s.l. (see Genera).